You should remember that there are probably other ways to improve your stats, like auntie ethels hair and the Ersatz eye from Volo in act 1.
Spellcasters don't really need feats imo, but for melee people, especially fighters, the usual is good. Sharpshooter, crossbow expert, Great Weapon Master, Polearm Master, Sentinel...
But I need to see their specific implementation first before creating full builds
