
Adapted Technique
Your innate abilities allow you to perform unique combat maneuvers. You gain the following benefits.
You learn one of the following maneuvers, as determined by your race. At 3rd level and again at 5th level, you learn a maneuver of your choice from among those available to the Battle Master archetype in the fighter class. If a maneuver you use requires your target to make a saving throw to resist the maneuver’s effects, the saving throw DC equals 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice).
You gain one superiority die, which is a d6 (this die is added to any superiority dice you have from another source). This die is used to fuel your maneuvers. A superiority die is expended when you use it. You regain your expended superiority dice when you finish a short or long rest.
Adopted Technique
By studying the unique abilities of others, you have learned to adapt their techniques to fit your own physiology. Your Strength or Dexterity score increases by 1. In addition, you learn one maneuver of your choice with a racial requirement, ignoring the requirement.
If a maneuver you use requires your target to make a saving throw to resist the maneuver’s effects, the saving throw DC equals 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice).
You gain one superiority die, which is a d6 (this die is added to any superiority dice you have from another source). This die is used to fuel your maneuvers. A superiority die is expended when you use it. You regain your expended superiority dice when you finish a short or long rest.
(This is intended to replace racial spellcasting, but unfortunately DNDBeyond doesn't support that. For simplicity's sake, this "feat" covers both Adapted Techniques and the tie-in feat Adopted Technique, because I don't want to write out all these maneuvers twice.)
Aarakocra (MPMM)
Windfury
Requires: Aarakocra
When you hit a creature with a melee weapon attack, you can expend one superiority die to surge with a burst of movement, moving up to half your movement speed. During this movement, you do not provoke opportunity attacks, and you can move through hostile creatures (though you cannot end your turn inside a creature). At the end of your turn, any creature you moved through must make a Dexterity saving throw or take slashing damage equal to one roll of your superiority die.
Aasimar (DMG)
Radiant Resolve
Requires: Aasimar
When you see a creature within 30 feet of yourself fail a saving throw, you can expend one superiority die to grant it resolve as a reaction, adding the superiority die to the saving throw and potentially causing it to succeed instead.
Dark Elf (PHB)
Guiding Moonlight
Requires: Dark Elf
When you hit a creature with a weapon attack, you can expend one superiority die to flare with silvery light, giving the target an ethereal glow for 1 minute. During this time, the target cannot benefit from invisibility, and the first attack made against it during this time has advantage.
Duergar
Mountains to Molehills
Requires: Duergar
When you would hit a creature with a melee weapon attack, you can expend one superiority die to enlarge your weapon briefly, before bringing it down upon a target. You add the superiority die to the attack’s damage roll, and if the target is larger than you, it must also make a Strength saving throw or fall prone.
Pallid Elf (EGTW)
Moonweaver’s Pallor
Requires: Pallid Elf
When you make an Intelligence (Investigation), an Intelligence (History), or a Dexterity (Stealth) check, you can expend one superiority die and add the superiority die to the ability check.
Fairy (MPMM)
Fae Trick
Requires: Fairy
When another creature would hit you with a melee attack, you can use your reaction and expend one superiority die to disappear briefly, forcing the attacker to make a Wisdom saving throw. On a failed save, the attack misses. Whether or not the attacker succeeded on the saving throw, you then reappear in an unoccupied location of your choice within 5 feet of the attacker.
Firbolg (MPMM)
Hidden Strike
Requires: Firbolg
When you hit a creature with a weapon attack, you can expend one superiority die to attempt to disappear from the target’s perception. You add the superiority die to the attack’s damage roll, and make a Dexterity (Stealth) check, contested by the target’s Wisdom (Perception) check. On a success, you become invisible to the target until the start of your next turn.
Air Genasi (EEPC/MPMM)
Jetstream
Requires: Air Genasi
When you hit a creature with a melee weapon attack, you can expend one superiority die to release a thunderous gale. The attack deals additional thunder damage equal to the number you roll on your superiority die, and you move up to half your movement speed. In addition, the target cannot take reactions until the start of your next turn.
Earth Genasi (EEPC/MPMM)
Stoneheart
Requires: Earth Genasi
When another creature damages you with a weapon attack, you can use your reaction and expend one superiority die to reduce the damage by the number you roll on your superiority die + your Constitution modifier.
Fire Genasi (EEPC/MPMM)
Wildfire
Requires: Fire Genasi
When you hit a creature with a weapon attack, you can attempt to set it ablaze. The attack deals additional fire damage equal to the number you roll on your superiority die, and the target is forced to make a Constitution saving throw. On a failed save, it is lit on fire, taking 1d6 fire damage at the end of each of its turns for 1 minute, or until a creature uses its action to douse the flames.
Water Genasi (EEPC/MPMM)
Wavecrest
Requires: Water Genasi
When you hit a creature with a weapon attack, you can batter it with the force of a tidal wave. The attack deals additional cold damage equal to the number you roll on your superiority die, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you push the target up to 15 feet away from you.
Githyanki (MPMM/MTOF)
Psionic Riposte
Requires: Githyanki
When another creature would hit you with a melee attack, you can use your reaction and expend one superiority die to psychically read its movements, adding the number rolled to your AC for that attack. If the attack misses, you can make one weapon attack against the attacker as part of the same reaction.
Githzerai (MPMM/MTOF)
Psionic Dodge
Requires: Githzerai
When another creature would hit you with an attack, you can use your reaction and expend one superiority dice to psychically read its movements, adding the number rolled to your AC for that attack. If the attack misses, you can teleport to an unoccupied location you can see within 30 feet of yourself as part of the same reaction.
Deep Gnome (MPMM)
Svirfneblin Subtlety
Requires: Gnome
When you make a Dexterity (Stealth), a Charisma (Deception), or a Charisma (Persuasion) check, you can expend one superiority die and add the superiority die to the ability check.
Lotusden Halfling (EGTW)
Thorncloak
Requires: Lotusden Halfling
On your turn, you can use a bonus action and expend one superiority die to cover your body with a growth of thorns. You gain temporary hit points equal to the superiority die roll + your Dexterity modifier, and if you are hit by a melee weapon attack while you have these temporary hit points, you can use your reaction to explode with spikes, forcing it to make a Dexterity saving throw. On a failed save, the attacker takes piercing damage equal to the superiority die roll + your Dexterity modifier.
Hexblood (VRGR)
Hexing Strike
Requires: Hexblood
When you hit a creature with a weapon attack, you can expend one superiority die to foretell doom upon your target. You add the superiority die to the attack’s damage roll, and the target subtracts the superiority die to the next saving throw it makes before the start of your next turn.
Tiefling (PHB)
Infernal Temper
Requires: Tiefling
When another creature damages you with a melee attack, you can use your reaction and expend one superiority die to erupt with fiery energy. The next time within 1 minute that you hit the attacker with a weapon attack, the attack explodes, dealing fire damage equal to one roll of the superiority die to creatures other than yourself within 10 feet of the target.
Triton (VGTM/MPMM)
Seafoam Snare
Requires: Triton
When you hit a creature with a weapon attack, you can expend one superiority die to mire it with seafoam. The attack deals additional cold damage equal to the number you roll on your superiority die, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, its speed is reduced to 0 until the start of your next turn.
Yuan-Ti (VGTM/MPMM)
Serpentine Strike
Requires: Yuan-Ti
When you make a melee weapon attack on your turn, you can expend one superiority die to increase your reach for that attack by 5 feet. If you hit, the attack deals additional poison damage equal to the number you roll on your superiority die.

This homebrew feature/feat are also available on the Homebrewery here: https://homebrewery.naturalcrit.com/share/nh2NcgyorCyh
It is recommended that you read through that document first to avoid confusion.