Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight | Thopter Squadron

Cards

All permanents on the battlefield (
Isilu and and
Thopter Squadron without a -1/-1 counter on it).

You are able to kill
Arcbound Ravager such that it won't have a -1/-1 counter on it when it dies.

Activate
Arcbound Ravager by sacrificing
Thopter Squadron.
When
Thopter Squadron dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to its replacement effect.
Resolve the
Arcbound Ravager ability.
Repeat.
Kill
Arcbound Ravager.
When
Arcbound Ravager dies, its persist ability triggers, returning
Arcbound Ravager from your graveyard to the battlefield. It will have no counters on it due to its modular ability.
Arcbound Ravager dies as a state-based action due to having 0 toughness.
Repeat from step 2.

This combo will end the game in a draw if it isn't interacted with, as it creates a mandatory infinite loop.

This combo has been estimated to be Spicy (Bracket 3-4+).