Joey, The Legion

Mad Grit — Whenever Joey deals combat damage to a player, untap all attacking creatures and after this phase, there is an additional combat phase. This ability triggers only once each turn.

Feral Frenzy — {1}{b}, {t}: Target creature gets a Deep Wounds counter. That creature's controller sacrifices it at the beginning of their end step unless they exert it. Activate only as a sorcery.

Legion (You may have four creatures as your commander
if they all have Legion.)