Infinite +1/+1 counters on a creatureInfinite combat phasesInfinite creature ETBInfinite creature LTBInfinite creature sacrifice triggersInfinite death triggersInfinite lifegainInfinite lifegain triggersInfinite mana creatures you control can produceInfinite untap of creatures you controlInfinite damage
How it works
Cast All-Out Assault by paying 2.
When All-Out Assault enters the battlefield, it triggers, causing you to get an additional combat and main phase after this one.
Move to your extra combat phase. All-Out Assault triggers, untapping each creature you control.
Declare Carmen as an attacker, triggering its second ability, returning Leonin Relic-Warder form your graveyard to the battlefield.
When Leonin Relic-Warder enters the battlefield, its first ability triggers, exiling All-Out Assault.
Move to your postcombat main phase, and activate Evereth by sacrificing Leonin Relic-Warder.
When Leonin Relic-Warder dies, its second ability and Carmen's first ability trigger.
Resolve the Carmen trigger, putting a +1/+1 counter on it and causing you to gain 1 life.
Resolve the Leonin Relic-Warder trigger, returning All-Out Assault from exile to the battlefield.
When All-Out Assault enters the battlefield, it triggers, causing you to get an additional combat and main phase after this one.