Homebrew Rules

-I use flanking, but as a flat +2 bonus to hit instead of advantage
-I use the “Slow Natural Healing” rule in the DMG. So for long rests, you recover ½ of your hit dice and can then spend them just like at a short rest. I modify it slightly in that if you would gain hit dice over your hit dice maximum, you can spend these without depleting your normal hit dice.
For example: you have 3/4 hit dice and would gain 2 from a long rest. You can spend one of these hit dice and still be at 4/4 hit dice, since by gaining two you are at a virtual 5/4 for the purposes of the long rest. These “excess” hit dice disappear if you do not spend them.
-Prone is more relevant as a condition. On standing up from being prone, you suffer opportunity attacks from creatures within reach. Keep in mind that when you go unconscious you go prone by default.
-I use the variant crit rule that maxes out damage on the dice and then has you roll damage dice on top of that. (Aka the Mike Mearls crit rule). This does not apply to extra sources of damage beyond the base weapon damage. For instance Sneak Attack/Divine Smite/Flame Tongue.
-I use XP for leveling. XP from monsters obviously, however I also award additional XP for roleplaying, completing objectives, or accomplishing any of the goals you list on your character sheet.
-Death Saves are changed. When a character succeeds three Death Saves, they automatically return to 1 hit point instead of being stable at zero.
-Strength and Intelligence are more relevant.
I use standard encumbrance for Strength, ignoring coin weight. Once you are encumbered your speed halves and you gain disadvantage on all Strength, Dexterity, and Constitution Checks or Saves. For Intelligence, I use the “Skill Point” system. You gain a number of skill points equal to your Intelligence modifier. Spend 1 to gain an extra skill, tool, or language proficiency, spend 3 to gain expertise in a skill or tool that you already are proficient in. If you have a negative modifier, you need to lose that many skills or language proficiencies.
-I have a homebrew system for Shields, detailed below. I understand this system may seem convoluted but trust me it runs pretty smoothly in actual play. As a reaction while holding a shield, you can raise it to grant yourself Temp HP equal to five times one minus the Shield’s Standard AC bonus (5[x-1] is the formula). You can also spend an action to raise it for a round, refreshing the Temp HP each turn. Someone with the Shield Master Feat can raise a shield as a bonus action. A shield cannot be raised while already raised, and this bonus stacks with other Temp HP sources. If you take damage with a shield raised that would exceed the temp HP bonus by Xfold, where x is the shield AC bonus, (so twofold for wooden shield, threefold for +1, etc.) the attacker can make an opposing ability check (based on the damage source, Strength for Melee, Dex for Ranged, etc.) vs the shield’s durability to split the shield, rendering it unusable until repaired. The DC for splitting a shield is 15, plus three times any magical bonuses the shield has. Wooden Shields are vulnerable to fire damage.
Ex. 1: A fighter raises a normal wooden shield as an action on their turn, granting them 5 temporary hit points on each subsequent turn in the round. A Goblin deals 10 damage to them, which exceeds the 5 temp HP twofold and means that the Goblin can roll to split the shield. The Goblin rolls a 2 and fails to split it. This means that on a second Goblin’s turn, the fighter would gain the 5 temporary hit points again since the shield is still raised from the initial action. This time, the second Goblin deals 10 damage, and has an opportunity to split the shield. They roll an 18, which meets the DC. This splits the shield.
Ex 2; A fighter raises a +2 Shield as a reaction, granting them 15 temporary hit points for the turn. A demon deals 60 points of damage, granting them a chance to split the shield. Rolling a 21, they fall 1 short of splitting the shield since the DC is 15 base plus 6 for the three times magic bonus of the +2 shield.
-It is impossible to raise someone from the dead without a bargain from some sort of extraplanar entity with command over the dead, unless within the “Revivify Window” of one minute. The only known exception is traveling into Hell to reclaim a soul personally. Infer from all of that what you will.