External Feats

i.e. Feats not authored by yours truly, but found in a D&D book. If the text is available on dnd5e.wikidot.com I link to it, otherwise I reproduce the text here.

Player's Handbook Feats

Alert: You're always on the lookout for danger.
Athlete: You have undergone extensive physical training.
Actor: You are skilled at mimicry and dramatics.
Charger: You can charge your foes.
Crossbow Expert: You have practiced extensively with the crossbo
Defensive Duelist: You know how to parry a weapon attack.
Dual Wielder: You've mastered fighting with two weapons.
Dungeon Delver: You're alert to the hidden traps and secret doors found in many dungeons.
Durable: You are hardy and resilient.
Elemental Adept: Prerequisite: The ability to cast at least one spell
You're skilled in casting spells related to your chosen element.
Grappler: Prerequisite: Strength 13 or higher
You've developed the skills necessary to hold your own in close-quarters grappling.
Great Weapon Master: You've learned to put the weight of a weapon to your advantage, letting its momentum empower your strikes.
Healer: You are an able physician, allowing you to mend wounds quickly and get your allies back in the fight.
Heavily Armored: Prerequisite: Proficiency with medium armor
You have trained to master the use of heavy armor.
Heavy Armor Master: Prerequisite: Proficiency with heavy armor
You can use your armor to deflect strikes that would kill others.
Inspiring Leader: Prerequisite: Charisma 13 or higher
You can spend 10 minutes inspiring your companions, shoring up their resolve to fight.
Keen Mind: You have a mind that can track time, direction, and detail with uncanny precision.
Lightly Armored: You have trained to master the use of light armor.
Linguist: You have studied languages and codes.
Lucky: You have inexplicable luck that seems to kick in at just the right moment.
Mage Slayer: You have practiced techniques in melee combat against spellcasters.
Magic Initiate: You gain some facility with simple magic spells even if you're in a spellcasting class.
Martial Adept: You have martial training that allows you to perform special combat maneuvers.
Medium Armor Master: Prerequisite: Proficiency with medium armor
You have practiced moving in medium armor.
Metamagic Adept: Prerequisite: Spellcasting or Pact Magic feature
You've learned how to exert your will on your spells to alter how they function.
Mobile: You are exceptionally speedy and agile.
Moderately Armored: Prerequisite: Proficiency with light armor
You have trained to master the use of medium armor and shields.
Mounted Combatant: You are a dangerous foe to face while mounted.
Observant: You are quick to notice details of your environment.
Polearm Master: You're skilled in using polearms in combat.
Resilient: You gain proficiency in a saving throw.
Ritual Caster: Prerequisite: Intelligence or Wisdom of 13 or higher
You have learned a number of spells that you can cast as rituals. These spells are written in a ritual book, which you must have in hand while casting one of them.
Savage Attacker: Once per turn when you roll damage for a melee weapon attack, you can reroll the weapon's damage dice and use either total.
Sentinel: You have mastered techniques to take advantage of every drop in any enemy's guard.
Sharpshooter: You have mastered ranged weapons and can make shots that others find impossible.
Shield Master: You use shields not just for protection but also for offense.
Skilled: You gain proficiency in any combination of three skills or tools of your choice.
Skulker: Prerequisite: Dexterity 13 or higher
You are an expert at slinking through shadows.
Spell Sniper: Prerequisite: The ability to cast at least one spell
You have learned techniques to enhance your attacks with certain kinds of spells.
Tavern Brawler: Accustomed to the rough-and-tumble fighting using whatever weapons happen to be at hand.
Tough: You're simply tougher than most.
War Caster: Prerequisite: The ability to cast at least one spell
You have practiced casting spells in the midst of combat.
Weapon Master: You have practiced extensively with a variety of weapons.

Official Supplements

Bigby Presents: The Glory of the Giants Feats

I have made these into racial feats for Ruokor. Just makes sense really.

Strike of the Giants: Prerequisites: Martial Weapon Proficiency, Ruokor race
You have absorbed primeval magic that gives you an echo of the might of giants.
Ember of the Fire Giant: Prerequisites: 4th Level, Strike of the Giants (Fire Strike) Feat, Ruokor race
You’ve manifested the fiery combat emblematic of fire giants.
Fury of the Frost Giant: Prerequisites: 4th Level, Strike of the Giants (Frost Strike) Feat, Ruokor race
You’ve manifested the icy might emblematic of frost giants.
Guile of the Cloud Giant: Prerequisites: 4th Level, Strike of the Giants (Cloud Strike) Feat, Ruokor race
You’ve manifested the confounding magic emblematic of cloud giants.
Keenness of the Stone Giant: Prerequisites: 4th Level, Strike of the Giants (Stone Strike) Feat, Ruokor race
You’ve manifested the physical talents emblematic of stone giants.
Soul of the Storm Giant: Prerequisites: 4th Level, Strike of the Giants (Storm Strike) Feat, Ruokor race
You’ve manifested the tempest magic emblematic of storm giants
Vigor of the Hill Giant: Prerequisites: 4th Level, Strike of the Giants (Hill Strike) Feat, Ruokor race
You’ve manifested the resilience emblematic of hill giants.

Tasha's Cauldron of Everything Feats

Artificer Initiate: You’ve learned some of an artificer’s inventiveness.
Chef: Time and effort spent mastering the culinary arts has paid off.
Crusher: You are practiced in the art of crushing your enemies.
Eldritch Adept: Prerequisite: Spellcasting or Pact Magic feature
Studying occult lore, you learn one Eldritch Invocation option of your choice from the warlock class.
Fighting Initiate: Prerequisite: Proficiency with a martial weapon
Your martial training has helped you develop a particular style of fighting.
Metamagic Adept: Prerequisite: Spellcasting or Pact Magic feature
You've learned how to exert your will on your spells to alter how they function.
Piercer: You have achieved a penetrating precision in combat.
Poisoner: You can prepare and deliver deadly poisons.
Shadow Touched: Your exposure to the Shadowfell's magic has changed you.
Skill Expert: You have honed your proficiency with particular skills.
Slasher: You've learned where to cut to have the greatest results.
Telekinetic: You learn to move things with your mind.
Telepathic: You awaken the ability to mentally connect with others.

Xanathar's Guide to Everything Feats

Bountiful Luck

Your people have extraordinary luck, which you have learned to mystically lend to your companions when you see them falter.

Prerequisite: Halfling

When an ally you can see within 30 feet of you rolls a 1 on the d20 for an attack roll, an ability check, or a saving throw, you can use your reaction to let the ally reroll the die. The ally must use the new roll.When you use this ability, you can't use your Lucky racial trait before the end of your next turn.

Dwarven Fortitude

You have the blood of dwarf heroes flowing through your veins.

Prerequisite: Dwarf

You gain the following benefits:

Increase your Constitution score by 1, to a maximum of 20.
Whenever you take the Dodge action in combat, you can spend one Hit Die to heal yourself. Roll the die, add your Constitution modifier, and regain a number of hit points equal to the total (minimum of 1).

Fade Away

Your people are clever, with a knack for illusion magic. You have learned a magical trick for fading away when you suffer harm.

Prerequisites: Gnome, level 5

You gain the following benefits:

Increase your Dexterity or Intelligence score by 1, to a maximum of 20.
Immediately after you take damage, you can use a reaction to magically become invisible until the end of your next turn or until you attack, deal damage, or force someone to make a saving throw. Once you use this ability, you can't do so again until you finish a short or long rest.

Prodigy

You have a knack for learning new things.

Prerequisites: Half-elf, Half-orc or Human

You gain the following benefits:

You gain one skill proficiency of your choice, one tool proficiency of your choice, and fluency in one language of your choice.
Choose one skill in which you have proficiency. You gain expertise with that skill, which means your proficiency bonus is doubled for any ability check you make with it. The skill you choose must be one that isn't already benefiting from a feature, such as Expertise, that doubles your proficiency bonus.

Second Chance

Fortune favors you when someone tries to strike you.

Prerequisite: Halfling

You gain the following benefits:

Increase your Dexterity, Constitution or Charisma score by 1, to a maximum of 20.
When a creature you can see hits you with an attack roll, you can use your reaction to force that creature to reroll. Once you use this ability, you can't use it again until you roll initiative at the start of combat or until you finish a short or long rest.

Squat Nimbleness

Prerequisites: Dwarf, Kobold, Halfling or Gnome

You are uncommonly nimble for your race. You gain the following benefits:

Increase your Strength or Dexterity score by 1, to a maximum of 20.
Increase your walking speed by 5 feet.
You gain proficiency in the Acrobatics or Athletics skill (your choice).
You have advantage on any Strength (Athletics) or Dexterity (Acrobatics) check you make to escape from being grappled.

Third-Party Supplements

Exploring Eberron Feats

Aereni Halflife

Prerequisite: Elf (Aereni)

You’ve undergone rituals that bind you to Irian and the Undying Court. Many who undergo this process have a desiccated appearance, similar to a mummy; it’s up to you whether you are affected in this way. Regardless of your appearance, you gain the following benefits:

Increase your Intelligence or Wisdom score by 1, to a maximum of 20.
You gain resistance to necrotic and radiant damage, and you have advantage on death saving throws.
If you cast a spell that deals necrotic damage, you can choose to have it inflict radiant damage instead.

Changeling Metamorphosis

Prerequisite: Changeling

Your ability to shapechange is more than skin deep. Increase your Constitution score by 1, to a maximum of 20. In addition, when you use your Shapechanging trait, you can choose one of the following benefits, which lasts until you use your Shapechanging trait again. Some of these benefits require specific physical features, such as gills or claws, that can be seen by observers.

Aquatic Adaptation. You adapt your body to an aquatic environment, sprouting gills and growing webbing between your fingers. You can breathe underwater and gain a swimming speed equal to your walking speed.

Darkvision. You adapt your eyes and gain darkvision with a range of 60 feet.

Natural Weapons. You grow claws, fangs, spines, horns, or a different natural weapon of your choice. Your unarmed strikes deal 1d6 bludgeoning, piercing, or slashing damage, as appropriate to the natural weapon you chose, and you are proficient with your unarmed strikes.

Focused Personas

Prerequisite: Changeling

You’ve developed personas that help you focus your talents. Work with your DM to define two unique personas —identities with distinct appearances and personalities. You gain the following benefits:

Increase your Charisma score by 1, to a maximum of 20.
Choose a tool and define a persona associated with it. While you are using your Shapechanging trait to assume the identity of that persona, you are proficient with that tool. If you are already proficient in it, your proficiency bonus is doubled for any ability check you make using that tool while assuming that persona.
Choose a skill you’re proficient in and define a different persona associated with it. While you are using your Shapechanging trait to assume the identity of that persona, your proficiency bonus is doubled for any ability check you make using that skill.

Superior Shifting

Prerequisite: Shifter

You have a strong connection to the beast within, strengthening your body and your ability to shift. You gain the following benefits:

Choose one of the ability scores affected by your subrace’s Ability Score Increase. Increase this ability score by 1, to a maximum of 20.
When you use your Shifting trait, the transformation lasts for ten minutes, until you die, or until you end it as a bonus action.
You can use your Shifting trait one additional time. You regain all uses when you complete a short or long rest.

Envoy Specialist

Prerequisite: Warforged

You have modified your body to perform a specific task, integrating a tool directly into your body. You gain the following benefits.

Increase one ability score of your choice by 1, to a maximum of 20.
You gain proficiency with one tool of your choice.
Choose one of these tools you are proficient with that weighs 10 pounds or less: an artisan’s tool, forgery kit, herbalism kit, poisoner’s kit, thieves’ tools, or a musical instrument. You have a working model of this tool integrated into your body. It can’t be removed, and as long as you have a hand free, you can make use of the integrated tool.
Your proficiency bonus is doubled when you make ability checks using this integrated tool.

Juggernaut Plating

Prerequisite: Warforged

Your armor is a part of you, strengthened by your life force. You gain the following benefits.

Increase your Strength or Constitution score by 1, to a maximum of 20.
When you use Integrated Protection to don light or medium armor, you can add your Constitution modifier to your Armor Class instead of your Dexterity modifier (to a maximum of +2 when using medium armor).
When you use Integrated Protection to don heavy armor, you have advantage on Strength saving throws and Strength (Athletics) checks to resist being knocked prone or moved against your will.
While it’s incorporated into your body, your armor can’t be targeted by any effect (such as heat metal or the antennae of a rust monster) against your will.

Morgrave Miscellany Feats

Chameleon

Prerequisite: Changeling

You have honed your natural shapeshifting powers. You gain the following benefits:

Increase your Charisma score by 1, to a maximum of 20.
You can use your Change Appearance trait as a bonus action.
You can use Unsettling Visage twice before completing a short or long rest.

Hierophant

Prerequisite: The ability to cast a druid or ranger spell.

You have strengthened your connection to the beasts of the natural world. You gain the following benefits:

You gain proficiency in either the Nature or Survival skill.
You learn the speak with animals spell and can cast it once without expending a spell slot. Once you do, you can’t do so again until you complete a short or long rest. Wisdom is your spellcasting ability for this spell.
You gain one use of the Wild Shape feature available to the druid class and can use it to shift into any beasts you have seen before with a CR rating 1/8 or below, including those with a swim or fly speed.
Once you do, you can’t do so again until you complete a short or long rest. If you have the Wild Shape feature from another source, you gain an additional use with the benefits and restrictions of that feature instead.

Moonspeaker

Prerequisites: Shifter, Weretouched Master feat, 8th level.

You call to the moon to entice your lycanthropic ancestors to further enhance your shifting abilities. You gain the following benefits:

Your Dexterity score increases by 1, to a maximum of 20.
Choose a shifter subrace other than your own. When you shift, you also gain the benefits of its Shifting Feature, in addition to your own.
If you are conscious when your shifting trait ends, you regain a number of hit points equal to your Constitution score, up to your Hit Point Maximum, instead of your Constitution modifier.

Spirit Rider

Prerequisite: Halfling or Valenar Elf

You learn an ancient ritual that creates a spiritual totem from a bracelet, figurine, tribal mask, or other item, that unites rider and mount in a sacred bond. While you possess your totem, you gain the following benefits:

You can communicate telepathically with your mount.
You have advantage on Animal Handling checks made to control your mount, and your mount has advantage on Acrobatics and Athletics checks.
You can communicate simple ideas through sounds and gestures with other creatures of the same type as your mount.

Warforged Colossus

Prerequisites: Warforged, Strength 13 or higher

As an unstoppable force on the field of battle, you gain the following benefits:

Increase your Strength by 1, to a maximum of 20.
You can use your reaction to reduce the distance you are moved against your will by up to 10 feet.
When you move at least 30 feet in a straight line right before you make a melee weapon attack using Strength and you hit, you can add your Strength modifier to the damage twice, instead of once.

Warforged Reclaimer

Prerequisites: Warforged, 6th level

You can transfer the power of magical armor you find during your travels into your integrated armor. Magical armor you absorb must have a rarity of very rare or lower and can’t be sentient.

Transferring the armor’s magical properties requires 8 hours of uninterrupted work, which you can complete when you finish a long rest, and destroys the armor in the process. If you repeat the process, the old enchantment is lost and the new one takes its place. If the armor’s magical properties include a curse, you always gain that property, and can’t replace it with a new enchantment unless you are targeted by the remove curse spell or similar magic as you complete the new enchantment.

Weretouched Master

Prerequisite: Shifter

The strength of your lycanthropic heritage increases, expanding your primal abilities. You gain the following benefits:

Your Dexterity score increases by 1, to a maximum of 20.
Choose a shifter subrace other than your own. You also gain the traits of that subrace, but not its ability score increase or shifting feature.
If you are conscious when your shifting feature ends, you regain a number of hit points equal to your Constitution modifier, up to your Hit Point Maximum.