House Rules

Let's establish some objectives:

The game should be fun for all the players.
The DM is a player.
The rules should be changed to make the game fun.
Fun should NOT be at the expense of others.
Joy requires risk. The game is not fun if there is no risk.
Stress and struggle can be fun if there's a positive outcome.
Pain for the sake of pain is not fun. The game is not fun if it feel unwinable.

These rules are the starting point. If, at any point, you're no longer having fun with the game, please talk with the DM and get the rules changed.

Flanking

From the core rule books about flanking.

If you regularly use miniatures, flanking gives combatants a simple way to gain advantage on attack rolls against a common enemy. A creature can’t flank an enemy that it can’t see. A creature also can’t flank while it is incapacitated. A Large or larger creature is flanking as long as at least one square or hex of its space qualifies for flanking. When a creature and at least one of its allies are adjacent to an enemy and on opposite sides or corners of the enemy’s space, they flank that enemy, and each of them has advantage on melee attack rolls against that enemy. When in doubt about whether two creatures flank an enemy on a grid, trace an imaginary line between the centers of the creatures’ spaces. If the line passes through opposite sides or corners of the enemy’s space, the enemy is flanked.

Feats

You can choose from the basic feats available to all players or cast your net into the darkened depths of the feat database from DnDBeyond. Access to the basic feats is guaranteed. The more exotic feats from the db may face DM review or revision to fit the narative of the universe.

A feat represents a talent or an area of expertise that gives a character special capabilities. It embodies training, experience, and abilities beyond what a class provides. At certain levels, your class gives you the Ability Score Improvement feature. Using the feats rule, you can forgo taking that feature to take a feat of your choice instead. You can take each feat only once, unless the feat’s description says otherwise. You must meet any prerequisite specified in a feat to take that feat. If you ever lose a feat’s prerequisite, you can’t use that feat until you regain the prerequisite. For example, the Grappler feat requires you to have a Strength of 13 or higher. If your Strength is reduced below 13 somehow — perhaps by a withering curse — you can’t benefit from the Grappler feat until your Strength is restored. Feats can be changed by connecting, in-game, with a professional in the newly desired feat and discussing with your DM about the conversion requirements.

Critical Results

A critical is defined as "rolling a maximum (or minimum) value on a decision die." For D&D this is rolling either a 1 or a 20 on the d20.

Natural Critical Success

When a player rolls a "natural 20" (a 20 on the 20-sided die) it results in the best possible outcome given the situation. A 20 on the die for an attack roll means a guaranteed hit and then doubling all the of die rolled for damage. That includes doubling all Sneak Attack and Smite damage die. A "nat 20" on an ability check means you are about to execute at the absolute maximum level, added with the characters native bonus to that ability. It does not mean you seduce the lich. It means, if a lich were capable of love, you would have inspired them to think about what the long term emotional ramification of their actions might be after they've dealt with the intruding party. Often, however, a nat 20 on perception, investigation or insight checks, will result in the DM revealing key information that may not have been considered. This is a reward for those skills predominately being used passively.

Dirty Critical Success

If rolling a 20 on a die is a "nat 20", then rolling an 18 and having a +2 bonus is a "dirty 20." While not immediately a success, there is a sliding scale of power which comes through the additional ability score. For example:

8 - Angus's intelligence check after a couple of beers.
10 - Average human skills.
13 - The best high-school quarterback's athletics.
15 - Zookeeper's animal handling during feeding time.
18 - Cirque de Soleil's acrobatics during a performance.
20 - An FBI internal affairs agent's insight into what's up.
23 - Republican Congressman's deception check
25 - Your shadow's stealth check
27 - Intimidation check of the Predator vs Arnold Schwarzenegger
30 - You peer behind the veil of reality with your perception check and see into the 6th dimension.

100 bad days make 100 good stories,
100 good stories make you interesting at parties

-- AJR

Critical failures are not intended to penalize an already disappointing situation. They are to act as narrative fuel and make for interesting situations.

Natural Critical Failure

The opposite side of the coin is when you roll a 1 on a d20. For ability checks, the result is absolutely a failure (even for reliable talent) but it does not mean death or dismemberment. Usually it'll mean some twist of bad luck and another roll to find out how bad. For example, if you roll a 1 on an attack, you might need to make another attack, but this time against the AC of a nearby ally. Or, for an ability check you might roll a 1 on perception, and then need to make an intelligence saving throw to see if you really believed the false vision you've just seen.

Dirty Critical Failure

If, for some bizarre reason, you roll more than a 1 on the die, but manage to add the roll UP TO a dirty 1 (i.e. you roll a 2 and then have a -1 in strength), then you have rolled the ever illusive dirty 1. You will not succeed. Your lack of success is so remarkable, you not only don't succeed, you make it impossible for another in your party to succeed. You, and another in your party chosen by the DM fail this round/check or, at the DM discretion, you fail this roll and also have disadvantage on your next roll.

Group Skill Checks

Occasionally, there will be a need for the party to collectively succeed (or fail) at a task. Some examples would be sneaking over the bandit's palisade, spending an evening studying the enemy's plan so you can know what to do, or ganging up on the barmaid to convince her to bail on the innkeeper, leave this cruddy down and go pursue her real passion: wizard familiar cosmetic upgrade spells. These types of collective checks fall into two categories, skill totals where the total output is measured, and skill threshold where each individual's ability to meet a threshold is evaluated.

Skill Totals

The battle is coming. The goblin army has been building outside of the fort's walls for hours now. More of them just keep coming out of the crags in the stony ground towards the mountains. You and your party have a few more hours to prepare before the attack happens... what do you do to prepare? This is an aggregate group skill check. The DM determines the threshold for success and when a player rolls a check, the results of that roll are added to a competing aggregate. After everyone has declared their "action", if the aggregate exceeds the threshold, the group succeeds.

Natural 20 - Counts as 40 points
Dirty 20 - Counts as 20 points
Natural 1 - Counts as -5 points
Dirty 1 - Counts as 0 points and bestows disadvantage to another player's roll. Maybe consider getting new dice :-)

Each player only gets a fixed number of actions (determined before the rolling begins) and might do one of the following:

Active Skill Check

A player, with proficiency in a specific skill, attempts to make a skill check to benefit the party. Example: The paladin rolls athletics to move large chunks of rubble up against the fort's doors to reinforce them.

Passive Skill Check

A player, with proficiency in a specific skill, assumes a 10 on the dice roll for a skill check, and if above a 15 for that skill, grants advantage to the rest of the party. Example: The bard takes a 10 on performance to get a few of the other guards together and start playing gym rat rage rock to motivate folks involved in preparations. (remember the rules about stacking (dis)advantage)

Expert Help

A player, with proficiency in a tangential skill, works with another player to provide expert assistance granting them an additional roll (this is not advantage, but a new roll added to the total). Example: The cleric uses their Religion proficiency to dredge up stories from mythologies about epic heroes standing at the edges of oblivion an laughing back. The paladin takes courage and rolls another athletics to add to the total.

Help

A player, without applicable proficiency, works with another player and assist them in their objectives granting the other character advantage on a roll. Example: The rogue doesn't know how to cook, but they know how to fetch ingredients. They help the cook by fetching components for the invigorating stew they've prepared for the guards, just before battle.

Success can also be on a sliding scale. Let's assume the total was 100 points:

<50 Points: only the party survives, and barely that. Everyone takes a point of exhaustion. All the NPCs perished in the fight and the fort was lost.
50-<80 Points: the fort is overrun, roll 2d12 and save those NPCs. You all take a point of exhaustion, but are on the other side of the mountains.
80-100 Points: the fort is overrun but most of you are able to escape early on when you see the path to success isn't possible. Roll 2d12, these NPCs are lost, but the rest survive.
100-120 Points: the fort is saved, but you are besieged. You have another day to decide on a course of action. Roll 1d12, these are today's losses.
120+: the fort is saved, the goblins are terrified and become unorganized, seeing an opportunity for a counter offensive, you and 1d12 guards leap out of the fort and take the fight to the goblins, looking to take out their shaman and claw.

Skill Threshold

Following on the heels of the retreating goblins, you discover their network of caves. The party sneaks into the caves to do some reconnaissance. This is a threshold group check. Each player rolls a check for the specific skill required. Each player tells the DM if they passed or failed and then tallies up the totals. If there are more successes than there are failures, then the operation is successful.

Natural 20: Counts as (2) successes
Dirty 20: Depending on the DC (yes, the DC could be as high as 25), counts as (1) success.
Natural 1: Counts as (2) failures
Dirty 1: Counts as a failure and grants disadvantage to one other player.

Death

I am completely unsatisfied with death. 0/10 stars. Would not recommend.
-- Me

These rules are **WIP** and I'd really like feedback/discussion. The problem I'm trying to solve: "Death in 5e doesn't feel heroic and is very disengaging from the game.
It's realistic, but not fun. And this is a game."

The problem with "being knocked unconscious" is you're immediately out of the game until you can be pulled back, and if you're moderately lucky, that means at least 5 rounds of combat you're out and then another 10 minutes of a short rest. Boooo... That's not fun. Most often, when D&D Rules let me down, I look to the Pathfinder 2E rules to see what's there (Archives of Nethys). We'll pull this apart and make a new version:

Hit Points, Healing, and Dying

All creatures and objects have Hit Points (HP). Your maximum Hit Point value represents your health, wherewithal, and heroic drive when you are in good health and rested. When you take damage, you reduce your current Hit Points by a number equal to the damage dealt. Some spells, items, and other effects, as well as simply resting, can heal living or undead creatures. When you are healed, you regain Hit Points equal to the amount healed, up to your maximum Hit Points.

Knocked Out and Dying

Creatures cannot be reduced to fewer than 0 Hit Points. When most creatures reach 0 Hit Points, they die and are removed from play unless the attack was nonlethal, in which case they are instead knocked out for a significant amount of time (usually 1 minute or more). When undead and construct creatures reach 0 Hit Points, they are destroyed. Player characters, their companions, and other significant characters and creatures don’t automatically die when they reach 0 Hit Points. Instead, they are knocked out and are at risk of death. At the GM’s discretion, villains, powerful monsters, special NPCs, and enemies with special abilities that are likely to bring them back to the fight (like ferocity, regeneration, or healing magic) can use these rules as well. As a player character, when you are reduced to 0 Hit Points, you’re knocked out with the following effects:

You immediately move your initiative position to directly before the turn in which you were reduced to 0 HP.
You gain the dying 1 condition. If the effect that knocked you out was a critical success from the attacker or the result of your critical failure, you gain the dying 2 condition instead.
If you have the wounded condition, increase your dying value by an amount equal to your wounded value. If the damage was dealt by a nonlethal attack or nonlethal effect, you don’t gain the dying condition; you are instead unconscious with 0 Hit Points.

Taking Damage while Dying

If you take damage while you already have the dying condition, increase your dying condition value by 1, or by 2 if the damage came from an attacker’s critical hit or your own critical failure. If you have the wounded condition, remember to add the value of your wounded condition to your dying value.

Death Saving Throws

When you’re dying, at the start of each of your turns, you must attempt a flat check with a DC equal to 10 + your current Dying Level to see if you get better or worse. This is called a recovery check. The effects of this check are as follows.

Critical Success - Your dying value is reduced by 2.
Success - Your dying value is reduced by 1.
Failure - Your dying value increases by 1.
Critical Failure - Your dying value increases by 2.

Conditions Related to Death and Dying

Dying

You are bleeding out or otherwise at death’s door. When you first gain this condition, you are knocked unconscious until the start of your turn. The initial Dying level is 1 + your current Wounded level. Dying always includes a value. If this value ever reaches Dying 4, you die.

If you lose the dying condition by succeeding at a recovery check you regain 1 HP and gain a level in Wounded.
If you receive natural healing (sleeping through the night, non-magical poultice, medicine check) that raises you above 0 HP, you loose all levels in the dying condition but still gain one level in Wounded until you can rest again and clear your levels in wounded.
If you receive magical healing that raises you above 0 HP, you loose all levels in Dying and gain no additional wounds

Dying Levels

Level	1	2	3	4
Actions	Bonus or move	Bonus or moce	Bonus	Final Act
Speech	Normal	No yells	Only falteringly	Final Words
Movement	Crawl only, 1/2 speed	Crawl only, 1/2 speed	--	--

Wounded

You have been seriously injured during a fight. Anytime you lose the dying condition, you become wounded 1 if you didn’t already have the wounded condition. If you already have the wounded condition, your wounded condition value instead increases by 1. If you gain the dying condition while wounded, increase the dying condition’s value by your wounded value. The wounded condition ends if:

Once per day, someone successfully restores Hit Points to you with a DC 12 + Wounded Level, Medicine Check
When you complete a long rest, you lose one level in Wounded. (Stacks with medicine check)
If you are magically restored to full Hit Points and rest for 10 minutes.

Dead

After you die, you can’t act or regain actions or be affected by spells that target creatures (unless they specifically target dead creatures), and for all other purposes you are an object. When you die, you are reduced to 0 Hit Points if you had a different amount, and you can’t be brought above 0 Hit Points as long as you remain dead. Some magic can bring creatures back to life, such as the resurrect ritual, raise dead or revivify spell.

I like Matt Mercer's "the more you die the harder it is to be resurrected mechanic, but I haven't had the opportunity to work out the details. If we get that far, we may need to talk about it.

When you are restored from death you gain the Resurrected condition. When you gain this condition, you may take one of the following actions and forego your ability to be Revified (Resurrection can still be used):

Final Words

You utter some final words that can be heard by all those within 60ft. As they are the dying words of a hero, they are indelible and can never be forgotten by those present. After this, your spirit leaves your mortal meat suit and joins the seas of the many.

Final Act

You use the last of your energy to do one last action. You cannot move from your square, but you can take an action. You can operate a device, cast a spell or do one final attack. After this effort, your body loses all its power and you surrender to the next adventure.

Resurrected

If you are restored to life by any means, you are considered Resurrected. This condition and its severity varies per spell, but generally: Effects:

Your max hit points = 1 / (Resurrection Level) of your original level rounded up.
All your skills have a negative penalty equal to your Resurrection Level

Clearing Effects

One week of rest clears one level of Resurrection
Greater Restoration clears a maximum of one level of Resurrection per day

Death Effects and Instant Death

Some spells and abilities can kill you immediately or bring you closer to death without needing to reduce you to 0 Hit Points first. If you are reduced to 0 Hit Points by a death effect, you are slain instantly without needing to reach dying 4. You have no final words or final act. If an effect states it kills you outright, you die without having to reach dying 4 and without being reduced to 0 Hit Points.

Massive Damage

You die instantly if you ever take damage equal to or greater than double your maximum Hit Points in one blow.

Items and Hit Points

Items have Hit Points like creatures, but the rules for damaging them are different. An item has an AC and Damage Resitance or Damage Threshold that reduce damage the item takes. If an item is reduced to 0 HP, it’s destroyed and cannot be rebuilt. If an item has less than 1/4 of its HP, it's considered broken and is not usable.

Fast Healing and Regeneration

A creature with fast healing or regeneration regains the listed amount of Hit Points each round at the beginning of its turn. A creature with regeneration has additional benefits. Its dying condition can't increase to a value that would kill it (this stops most creatures from going beyond dying 3) as long as its regeneration is active. If it takes damage of a type listed in the regeneration entry, its regeneration deactivates until the end of its next turn, including against the triggering damage.

OP/RP

In Role Playing, "The Rule of Cool" strongly applies and the DC of a challenge comes down as the players engage with the story in a character consistent way. For example, if your character can talk with one of the BBEG's lieutenant and the player actually provide a story consistent argument why the BBEG is no worth the lieutenant's time and efforts, the DC lowers from DC25 to DC22. And if the rest of the part pitches in to pile on that, the DC can lower further.

Characters are rewarded in-game by engaged player actions and discussions.

Additionally, if a player is not comfortable with RP'ing yet, they can describe the desired outcome rather than the details of the conversation. The DC will be set appropriately based off the character's skill set and the likeliness of the outcome. Think creatively. The solution is not programmed and can be approached from many directions. Creative solutions are reward and encouraged. Heroism (not recklessness) is also encouraged and rewarded.

Character Redesign

Sometimes players choose skills and traits they think will be amazing but turn out to be underused or dull in the field. We have options to solve this!

Talk with your DM and describe what's not fun and what you expected. The game may just change because of it.
Consider the skill or ability you're not satisfied with, what about it would you change specifically to make it fair and fun. Remember what you can do, so can the enemy.
Consider multi-classing or building a plan for your character's future
Talk with your DM about changing feats or skills. You may have to go on a quest to change over to the new set.
Talk with the DM about maybe respecing your entire character. We'll have to come up with a good in-story reason why that's something that can happen.
If all else fails, talk with your party about maybe choosing a new character to join. See how the other folks feel about the current party synergy, stories and makeup. Then if you still want to proceed, talk with the DM about the new plan.

Remember, D&D is supposed to be fun. If you're not having fun, it's time to have a conversation with people and see what can be changed.

Minions

This work is greedily stolen from Matt Colevile and team from MCDM.
Specifically the Flee, Mortals! monster book.

tl;dr - Minions are explody. They die if they take any damage. If you line up the minions, you can kill several with one attack.

A minion is a weak foe, designed to allow GMs to create dramatic combat encounters with hordes of enemies without overwhelming the characters. In fact, an encounter with minions makes characters feel heroic, since they can take on a myriad of foes and live to tell the tale. However, minions still make threatening foes. Killing a minion still requires penetrating their defenses, and characters can’t just shrug off damage from minion attacks. So how do minions make running a horde of enemies quick and easy for the GM?

Minions are simple to run. Their stat blocks are small and uncomplicated.
Minions act quickly. They don’t multi-attack, roll for damage, or take unique bonus actions or reactions, so their turns aren’t long.
Minions die fast. A character can kill several minions with a single weapon attack!
Minions have strength in numbers. Their attacks can be grouped together to make them deadlier and faster to use at the table.

No Hit Dice

Minions have hit points but no Hit Dice, simplifying their design. Minions can’t spend Hit Dice to heal during a short rest because they have none.

No Damage Rolls

Minions don’t roll for damage because their attacks deal a static amount of damage. They also can’t score critical hits.

Shared Turns

Typically, all minions of the same stat block act on the same turn. Since they share a turn, the minions can each move into position then each use an action if they wish, instead of each moving and taking an action individually.

Minion Trait

Every minion has the Minion trait, which affects the creature in the following ways:

If the minion takes any damage from an attack or as the result of a failed saving throw, their hit points are reduced to 0.
If the minion takes damage from another effect, they die if the damage equals or exceeds their hit point maximum; otherwise they take no damage.

Overkill Attacks

Powerful weapon attacks can kill more than one minion in a single maneuver called an overkill attack. As already discussed, a weapon attack requires only 1 point of damage to reduce a minion to 0 hit points, regardless of their hit point maximum. However, when a weapon attack’s damage does exceed the target minion’s hit point maximum, the attack becomes an overkill attack and the damage dealt beyond the minion’s hit point maximum becomes overkill damage. Overkill damage can be applied to a second minion who has the same stat block as the target and is in overkill range. Damage against the second minion is counted as if you made a weapon attack against them; since it only takes 1 point of weapon damage to reduce a minion to 0 hit points, any amount of overkill damage immediately knocks them out. But wait, it gets better—if the initial attack’s overkill damage exceeds the second minion’s hit point maximum, the leftover overkill damage can roll over to a third minion, and so on! In other words, for each time the overkill damage exceeds the new target’s hit point maximum, the attacker can choose an additional minion to reduce to 0 hit points.

For example, when a weapon attack deals 18 damage to a minion with a hit 
point maximum of 5, the overkill damage is 13. If there are three additional 
minions of the same stat block in overkill range, they can all three be 
immediately reduced to 0 hit points, since the overkill damage exceeded 
the target’s hit point maximum more than twice over.

Overkill attacks can’t be made as part of an opportunity attack.

Overkill Range

Minions must be within a certain range to qualify for an overkill attack, determined by whether the attack is a melee or ranged attack.

Melee Overkill Attacks

When a creature hits a minion with a melee weapon attack, other minions within reach of the attack are in overkill range and can be chosen as additional targets for an overkill attack. The overkill attack can’t target minions outside the weapon attack’s reach.

Lady Ulnock the paladin battles a horde of goblin minions (each with 6 hit 
points). She hits a goblin minion with her longsword and uses Divine Smite, 
dealing 8 slashing damage and 11 radiant damage to the target for a total 
of 19 damage. Since Lady Ulnock dealt 13 points of overkill damage—more
than the hit point maximum of two additional minions—she can choose up
to three additional goblin minions within 5 feet of her (the reach of her
longsword attack) and reduce them to 0 hit points. If there are no other 
goblin minions within 5 feet of Lady Ulnock, she can’t damage additional 
minions with this attack.

Ranged Overkill Attacks

When a creature hits a minion with a ranged weapon attack, other minions in a line originating from the creature in the direction of the target, to a distance equal to the weapon’s short range, are in overkill range and can be chosen as additional targets for an overkill attack. The overkill attack can’t target minions outside the line or beyond the weapon’s short range.

Perigold Quickfingers the rogue is hidden and takes aim at a group of 
zombie minions (each with 6 hit points) with his light crossbow (which 
has a short range of 80 feet). He hits a zombie minion with his crossbow, 
dealing extra damage thanks to his Sneak Attack, for a total of 14 
damage. Since Perigold dealt 8 points of overkill damage—more than 
the hit point maximum of one additional minion—he can choose up to 
two additional zombie minions in an 80-foot-long line extending from
Perigold in the direction of the target, reducing them to 0 hit points. If
there are no other zombie minions in the line, then Perigold can’t 
damage other minions with this attack.

Group Attacks

Each minion has at least one group attack action that speeds up play. In a group attack, two to five minions of the same stat block who share a turn can all use their action to join the attack, provided the target is within the original attack’s reach or range for each minion.

Make a single attack roll for the group attack. It counts as one attack.
A group attack roll gains a +1 bonus to the attack roll for each minion who joins the attack. (For example, if four goblin minions make a group attack together, the attack roll has a +4 bonus.)
If the group attack hits, multiply the damage by the number of minions who joined that group attack. (For example, if four goblin minions hit with a group attack that deals 1 damage, their group attack deals 4 damage.)

The GM decides how many minions join a group attack. For instance, if five minions surround a target, the GM may decide to have all five attack at once to speed up combat, or may break up the attacks among smaller groups to increase the odds that some minions hit while others miss. A single minion can even use their group attack action on their own—they make the attack as a normal creature would, and simply don’t benefit from the group bonuses described above.

Advantage and Disadvantage

A group attack is only made with advantage or disadvantage if all the minions joining the group attack have advantage or disadvantage on the attack roll. Otherwise, the attack is made without advantage or disadvantage.

Cover and Concealment

If a target has cover or concealment from some but not all minions, the GM should divide the minions into multiple groups based on the type of cover or concealment they have, then make a separate attack for each group.

Target Response Effects

If a group attack triggers a reaction or similar effect that would normally affect a single attacker, such as the fire shield or hellish rebuke spell, the target of the group attack picks one minion who joined the attack to be affected by the effect.

Group Opportunity Attacks

If a creature provokes an opportunity attack from more than one minion of the same stat block at a time and those minions have a melee group attack action, the minions can each use their reaction to join a group attack as an opportunity attack.

Group Saving Throws

Though minions often make saving throws individually, there are times when rolling individual saving throws for each minion could slow down the fight, like when a cleric surrounded by eighteen shade minions uses Turn Undead. When many minions with the same stat block need to make a saving throw against the same effect at the same time, you can make one saving throw for a group of up to five minions at a time. All minions in a group use the result of the saving throw.

For instance, if thirty-four goblin minions need to make
a saving throw against a hypnotic pattern spell, the minions
would make a total of seven saving throws against the spell:
six for thirty minions divided into six groups of five, and
one more save for the remaining group of four minions.

Special Traits

Many minions have traits that give them strength in numbers but become less powerful as their allies are defeated. For example, an enemy who starts their turn within 5 feet of three or more goblin lackeys must succeed on a saving throw or take damage from the lackeys’ Tiny Stabs trait.

Challenge Ratings

Minions have a challenge rating just like any other creature. However, their experience point value depends on their challenge rating. Aside from their damage output, the Minion trait, and their experience point value, a minion’s statistics are on par with a standard creature of the same challenge rating. When the rules reference a challenge rating, such as the polymorph spell or the cleric’s Destroy Undead feature, use the minion’s listed challenge rating as normal. For instance, a 5th-level cleric can affect Undead creatures with a challenge rating of 1/2 or lower with their Destroy Undead feature—so this feature can affect rotting zombie minions (CR 1/4) but not shade minions (CR 1).

Player Handbook