Below are the Knacks available to Rangers. If a Knack has a prerequisite, you can learn it at the same time that you meet it them. Knacks use your Spell save DC for saving throws:
 

Alpine Adept

Prerequisite: proficiency in Athletics
You are an expert climber. You gain a 30-foot climbing speed and Resistance to bludgeoning damage you take from falling. If you already have a climbing speed, it increases by 10 feet. Finally, you can add double your Proficiency Bonus to any Athletics checks that you make.
 

Aquatic Adept

Prerequisite: proficiency in Athletics
You can swim through the water like a native creature of the sea. You gain a swimming speed of 30 feet, and you can hold your breath for twice as long underwater. If you already have a swimming speed, it increases by 10 feet. Finally, you can add double your Proficiency Bonus to any Athletics checks that you make.
 

Arctic Adept

Prerequisite: proficiency in Survival
You have adapted to the frozen tundra. You gain Resistance to Cold damage, and you add your Ranger level to any Survival checks you make in arctic, snowy, or tundra environments.
 

Cavern Adept

Prerequisite: proficiency in Perception
You are especially skilled at navigating the winding tunnels under the earth. You gain Darkvision out to a range of 60 feet. If you already have Darkvision, its range increases by 30 feet. As a bonus action, you can close your eyes and focus your senses to gain Tremorsense out to a 30-foot radius. You must concentrate on this sense as if concentrating on a spell.
 

Desert Adept

Prerequisite: proficiency in Survival
You have adapted arid deserts. You gain Resistance to Fire damage, and you can add your Ranger level to any Survival checks you make in extreme heat or desert environments.
 

Favoured Foe

You are especially adept at studying, tracking, and hunting a specific type of enemy. Choose one creature type, two races of Humanoid (such as Gnolls and Orcs), or one organization (like a thieves' guild or an evil cult) as your Favored Foe. When you make an ability check to recall knowledge, hunt, or track a Favored Foe, treat a d20 roll of 9 or lower as a 10.
You can learn this Knack more than once, but you choose a new Favored Foe each time that you learn it.
 

Fell Handed I

Prerequisite: 6th-level Ranger
You pour the wrath of the wilds into each strike. Each time you hit your Quarry with an attack, your critical hit range is increased by 1. However, after you score a critial hit against it, your critial hit range against it returns to normal. For example, after you hit your Quarry with one attack, your attacks score a critial hit against it on a roll of 19-20 on the d20. After two hits, a roll of 18-20 on the d20. But, if you score a critial hit on it, it returns to 20 on the d20.
 

Fell Handed II

Prerequisite: 9th-level Ranger, Fell Handed I
Once per turn when you make an attack against your Quarry, you can give yourself advantage on your attack roll. However, if this attack hits, you do not add your Quarry bonus damage.
 

Hedge Knight I

Prerequisite: Strength of 13
Though you live in the wilderness you still have some formal military training. You gain proficiency with Heavy Armour and you learn to speak, read, and write one additional language.
 

Hedge Knight II

Prerequisite: 3rd-level Ranger, Hedge Knight I
Though you are a wanderer you have a basic understanding of chivalry and politics. You learn to speak, read, and write a language of your choice, and you gain proficiency in History, Persuasion, or Religion. Whenever you make an abiltiy check with any of the skills above, you use Wisdom in place of the normal ability score.
 

Herbalist I

Prerequisite: proficiency in Medicine
You have an extensive knowledge of plants and their healing properties. You gain proficiency with Herbalism, and you automatically succeed on Medicine checks made to stabilize creatures at 0 hit points if you use a Herbalism Kit. Finally, you can add double your Proficiency Bonus to any Medicine or Herbalism checks that you make.
 

Herbalist II

Prerequisite: 3rd-level Ranger, Herbalist I
You have learned to use natural plants and herbs to create healing salves. Over the course of a long rest, you can spend 1 hour using a Herbalism Kit to create one potion of healing at a potency related to your character level. This potion retains its potency until the end of your next long rest.
Simple Healing Tincture: level 3-7
Healing Tincture: level 8-12
Advanced Healing Tincture: level 13-17
Supreme Healing Tincture: level 18-20
 

Herbalist III

Prerequisite: 6th-level Ranger, Herbalist I, II
When you use your Herbalism Kit to craft potions of healing during a long rest, you craft a number of these potions equal to 1 + your Wisdom modifier (minimum of 2). These Potions are of the rarity in the Herbalism II Knack, and expire at the same rate.
 

Jungle Adept

Prerequisite: proficiency in Survival
You have adapted to the deadly jungle. You gain Resistance to Poison damage, and you add your Ranger level to all Survival checks you make in tropical forest or jungle environments.
 

Naturalist I

Prerequisite: proficiency in Nature
You are an intuitive scholar of the wild. You use Wisdom, in place of Intelligence, for Nature checks. Also, you can use a bonus action on each turn to make a Nature check to recall knowledge about one Beast or Plant you can see. Finally, you can add double your Proficiency Bonus to any Nature checks that you make.
 

Naturalist II

Prerequisite: 9th-level Ranger, Naturalist I
Your understanding grants you a mystical connection to the natural world. At the end of each short or long rest, you gain benefits as if you had cast the Commune with Nature spell.
 

Natural Regeneration

Prerequisite: 3rd-level Ranger
During a short rest, you can recover spell slots of a combined level equal to your Wisdom modifier (minimum one 1st-level). Once you regain spell slots in this way, you must complete a long rest before you can use this feature again.
 

Planar Adept

Prerequisite: 9th-level Ranger, proficiency in Survival
You have learned to survive on one of the great Planes of the multiverse. Choose one of the Extraplanar Locations listed below, and gain Resistance to that Plane's corresponding damage type:
Acid: Oblivion Bog [Shadowfell], Isalan [Astral Realms], Nihal [Far Realms],
Cold: Shinaelestra [Feywild], Elemental Water [Water Planes], Delban [Far Realms],
Fire: Astrazalian [Feywild], Sokenzan Mountains [Kawigama], Gauntlgrym [Underdark], Elemental Fire [Fire Planes], Avernus [Baator],
Force: Thyrin Gol [Shadowfell], Blingdenstone [Underdark], Elemental Earth [Earth Planes],
Lightning: Lake Kamitaki [Kamigawa], Quasi-Elemental Lightning [Air Planes], Ravnica [Astral Realms,
Necrotic: Gloomwrought [Shadowfell], Takenuma Swamps [Kamigawa], Atropus [Far Realms],
Poison: Murkendraw [Feywild], Jukai Forest [Kamigawa], Menzoberranzan [Underdark],
Psychic: Letherna [Shadowfell], Glimmersea [Underdark], Gibbeth [Far Realms],
Radiant: Towabara [Kawigama], Zendikar [Astral Realms], Quasi-Elemental Radiance [Fire Planes],
Thunder: Hedgewick [Feywild], The Darklands [Underdark], Elemental Air [Air Planes],
Also, you add your Ranger level to any Survival checks you make to navigate and survive the hostile effects of that entire Plane (In brackets). When you make a Knowledge or Survival roll in the prefered area, treat a d20 roll of 9 or lower as a 10. You can learn this Knack more than once, but you must choose a different Plane of existence each time you do.
 

Rider I

Prerequisite: proficiency in Animal Handling
Any time you make an Animal Handling check to tame, train, or control a mount, you treat any roll of 7 or lower on the d20 as an 8. Also, when you mount or dismount a trained mount, it only costs you 5 feet of movement instead of half. Finally, you can add double your Proficiency Bonus to any Animal Handling checks that you make.
 

Rider II

Prerequisite: 3rd-level Ranger, Rider I
You learn the Mounted Warrior Fighting Styles, and you can ride trained mounts that are equal to you in size or larger. If you already know the Mounted Warrior Fighting Styles you learn another Fighting Styles of your choice.
 

Rider III

Prerequisite: 6th-level Ranger, Rider I, II
You are a master of mounted combat. When you are riding a mount and it is hit by an attack, you can use your reaction to become the target of that attack instead. Also, if your mount is forced to make a saving throw while you are riding it, it gains a bonus to its saving throw equal to your Quarry Die.
 

Slayer I

Prerequisite: 3rd-level Ranger, proficiency in Perception
When you hit a creature with an attack, you can mark it as your Quarry, expending a use of Ranger's Quarry as normal, and applying the bonus damage and other benefits on hit. Finally, you can add double your Proficiency Bonus to any Perception checks that you make.
 

Slayer II

Prerequisite: 6th-level Ranger, Slayer I
Your tracking abilities have become supernaturally accurate. You can mark a creature as your Quarry by studying signs of its passing, like tracks, left within the past 24 hours. Also, when you mark a creature as your Quarry, the mark lasts indefinitley and only ends if you mark another creature.
 

Slayer III

Prerequisite: 14th-level Ranger, Slayer I, II
Once on each of your turns when you hit your Quarry with an attack, you can force it to make a Constitution saving throw. On a failed save, you choose if it is Blinded, Deafened, unable to speak, or Restrained until the start of your following turn.
 

Stalker I

Prerequisite: proficiency in Stealth
You are a master at remaining undetected in the wilderness. You have advantage on Stealth checks you make to hide while you are in natural environments. Finally, you can add double your Proficiency Bonus to any Stealth checks that you make.
 

Stalker II

Prerequisite: 3rd-level Ranger, Stalker I
You have learned to hunt your prey while remaining unseen. You can take the Hide action as a bonus action on your turn.
 

Stalker III

Prerequisite: 9th-level Ranger, Stalker I, II
You cannot be tracked, even by magic. You are always under the effects of the Nondetection spell, and you can't be tracked by Divination magic or magical means unless you wish to be.
 

Stalker IV

Prerequisite: 14th-level Ranger, Stalker I, II, III
Your mythic skill allow you to become undetectable. Any time you take a Hide action, you, and anything you are wearing or carrying, becomes invisible until the start of your next turn. This effect instantly ends if you Cast a Spell, or you attack or force a creature to make an ability check or saving throw.
 

Strider I

Prerequisite: proficiency in Survival
You ignore the effects of difficult terrain imposed by natural environments, you cannot become lost so long as you can see the night sky, and you and up to 10 creatures who travel with you don't have travel slowed by natural difficult terrain. Finally, you can add double your Proficiency Bonus to any Survival checks that you make.
 

Strider II

Prerequisite: 3rd-level Ranger, Strider I
Once in your sights, you pursue your foes relentlessly. You can take the Dash action as a bonus action on your turn.
 

Strider III

Prerequisite: 6th-level Ranger, Strider I, II
You can surmount almost any obstacle that would block your path. Your walking speed increases by 10 feet, and you ignore the effects of difficult terrain imposed by any spell, magical phenomena, or any other supernatural effect.
 

Strider IV

Prerequisite: 14th-level Ranger, Strider I, II, III
You move through the world unhindered by even the most powerful magic and restraints. You are always under the effects of a Freedom of Movement spell while conscious.
 

Student of the Wild

Time in the wild has honed your skills. You gain proficiency in two skills of your choice from the Ranger class skill list. You can learn this Knack more than once, but you choose two new Ranger class skills each time that you learn it.
 

Survivor I

Prerequisite: 6th-level Ranger
Your time in the wilds has hardened your body. As a bonus action on your turn, you can grant yourself temporary hit points equal to your Constitution modifier (minimum of 1).
 

Survivor II

Prerequisite: 9th-level Ranger, Survivor I
Your body can rapidly recover from injury. When you expend a Hit Die to regain hit points, you regain additional hit points equal to your Wisdom modifier (minimum of 1 hit point).
 

Survivor III

Prerequisite: 14th-level Ranger, Survivor I, II
When you make a death saving throw, you add your Wisdom modifier to the roll (minimum of +1). If the result of your roll is 20 or higher, it is as if you had rolled a 20 on the d20.
 

Trapper I

You are an expert in quickly creating traps. You gain proficiency with Thievery, and you have advantage on ability checks to identify traps nearby. Also, during a long rest, you can use a Silversmith Pouch and scrap to craft a number of Beginner Trap equal to your Proficiency Bonus. These traps break at your next long rest. As an action (separate from setting it), you can hide a Trap. Creatures have disadvantage on their saving throws against Traps if they are unaware of them. To detect a hidden Trap, a creature must make a successful Investigation or Perception check against your Spell save DC.
 

Trapper II

Prerequisite: 6th-level Ranger, Trapper I
Your skills as a Trapper have grown. So long as you have enough natural material and rope, you can craft a number of Trap at a skill you can use, equal to your Proficiency Bonus during a Short Rest. Once you set your Traps, they last until triggered or destroyed.
 

Urban Adept

Prerequisite: proficiency in Investigation
Your survival skills are adapted to the seedy underbellies of settlements and civilization. You learn to speak, decode, and leave messages in Thieves' Cant, the language of criminals. Moreover, once you complete a long rest in a settlement, you add your Quarry Die to any ability check you make to gather information on that settlement's factions, underworld, or any important infamous figures or creatures. Finally, you can add double your Proficiency Bonus to any Investigation checks that you make.
 

Wild Insight I

Prerequisite: proficiency in Insight
You can verbally communicate with and understand Beasts. However, when communicating with a Beast, its awareness and ability to recall knowledge is limited by its Intelligence. Finally, you can add double your Proficiency Bonus to any Insight checks that you make.
 

Wild Insight II

Prerequisite: 3rd-level Ranger, Wild Insight I
Your bond with the wild allows you to conjure bestial spirits. You always have the Find Familiar spell prepared, but it doesn't count against the spells you prepare each day. When you cast Find Familiar, its creature type is always Fey.
 

Woodsman

You are familiar with forests, trees, and raw timber. You gain proficiency with Carpentry, and you have advantage on ability checks to identify and construct things from wood. Also, during a long rest, you can use a set of Woodcarver's Tools and raw wood to craft a number of arrows, bolts, clubs, javelins, and quarterstaffs equal to your Proficiency Bonus.