Lux Arcadia (Undefeated Bahamut Chronicle); via End Action
Merlin (Seven Deadly Sins); via Infinity
Gray Boy (Worm)
Overdrive (Saga Frontier); when combined with the Stasis Rune
Alphamon (Digimon) can use its signature "Alpha InForce" to repeat any attack it lands a countless amount of times in a single instant, continueing until its opponent is defeated.
After acquiring the Rhythm Badge, Miles "Tails" Prower (Sonic the Hedgehog) is able to perform the Rapid Tails Attack, a continuous, uninterrupted chain of tail attacks, only ending when he chooses to end it.
Notorious B.I.G. (JoJo's Bizarre Adventure Part V/5: Golden Wind/Vento Aureo)
Johnny Joestar's (JoJo's Bizarre Adventure Part VII: Steel Ball Run) Stand, Tusk ACT 4 has the power of Infinite Rotation, the damage caused by it is infinite and will never end unless Johnny were to apply another similar rotation moving the other way, resulting in them cancelling each other out.
Lux Arcadia (Undefeated Bahamut Chronicle) via End Action.