Alright, I'll try to put all the relevant feats from 5e into one place. Anything that isn't covered by the class/race features.
Alert: Most likely would be heightened senses, since you can't be surprised and enemies can't get advantage against you for being unseen.
Dungeon Delver: Advantage against anything trap related. Also gains resistance to damage from traps.
Elemental Adept: Ignores resistances to acid, cold, fire, lightning, and thunder. (You can take this feat more than once. So each choice would apply).
Lucky: Luck manipulation (already stated in a previous comment, but wanted to restate it).
Mobile: Adds speed, can move over difficult terrain while dashing normally.
Observant: Also enhanced senses.
Sentinal: Can stop an opponent trying to flee from fleeing by reducing their speed to 0 (not sure what it would be but it's something). "When you hit a creature with an opportunity attack, the creature's speed becomes 0 for the rest of the turn."
Sharpshooter: Increases range of ranged attacks, ignores cover that isn't total cover and can sacrifice accuracy for more power.
Skulker: Better stealth.
Spell-Sniper: Doubles spell range for spells that require an attack roll. Ignores cover that isn't total cover.
War Caster: Can cast even with hands full, makes it harder to break concentration on spells.
Crossbow Expert: Can use ranged weapons in close range and ignores loading crossbow.
Acrobat: Makes them better at Acrobatics, has a chance of ignoring difficult terrain.
Animal Handler: Makes them better at calming and befriending animals.
Brawny: Better at Athletics. Counts as one size larger for lifting strength (basically doubles lifting strength). On that note, there are a lot of features that make you count as one size larger for lifting strength. Not sure if those would stack.
Diplomat: Makes them better at Persuasion. Can charm someone as long as they aren't hostile.
Empathic: Makes them better at Insight. They can use this Insight to be able to attack their opponent in more effective ways. "You can use your action to try to get uncanny insight about one humanoid you can see within 30 feet of you. Make an Insight check contested by the target's Deception. If your check succeeds, you have advantage on attack rolls and ability checks against the target until the end of your next turn."
Menacing: Makes them better at Intimidation. Can frighten opponents (possibly minor fear manipulation?)
Perceptive: Heightened senses.
Silver-Tongued: Better deception. "If your check succeeds, your movement doesn't provoke opportunity attacks from the target and your attack rolls against it have advantage; both benefits last until the end of your next turn or until you use this ability on a different target"
Bountiful Luck: More Luck Manipulation.
Dwarven Fortitude: Minor healing (or Regenerationn idk). "Whenever you take the Dodge action in combat, you can spend one Hit Die to heal yourself."
Fade Away: Invisibility. "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. "
Fey Teleportation: I think it's self explanatory.
Infernal Constitution: Resistance to cold and poison.
Second Chance: "When a creature you can see hits you with an attack roll, you can use your reaction to force that creature to reroll."
I might have missed a few from 5e. I'll see what I can find from other editions later. I think we should get feats and race features out of the way first before delving into spells and such.