Edited to account for post above me, and its missing upvote.
Barbarian (Primal Champion) 23 Does what you want from a capstone; break the rules but not break the game. (Cough...druid..)
Bard (Superior Inspiration) 16
Cleric (Divine Intervention Auto) 20
Druid (Archdruid) 20
Fighter (Third Extra Attack) 19 Extra Attacks are already bad, this is just worse.
Monk (Perfect Self) 21
Paladin (Sacred Oath Feature/Varies) 19
Ranger (Foe Slayer) 18
Rogue (Stroke of Luck) 20
Sorcerer (Sorcerous Restoration) 20
Warlock (Eldritch Master) 18 Too little too late.
Wizard (Signature Spell) 20