Umbral Collar Zealot + Furystoke Giant + Thran Vigil

Umbral Collar Zealot

Furystoke Giant

Thran Vigil

How it works

1. Activate Umbral Collar Zealot by sacrificing Furystoke Giant.
2. When Furystoke Giant dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Thran Vigil triggers, putting a +1/+1 counter on Furystoke Giant.
4. Resolve the Umbral Collar Zealot ability.
5. Repeat.

This crafty loop relies on Furystoke Giant entering the battlefield to grant its activated tapping ability to your crew, though its real magic here is its built-in persist mechanic that lets it bounce back from the graveyard with a -1/-1 counter. By feeding that same Furystoke Giant to Umbral Collar Zealot, you trigger Thran Vigil, which uses the card leaving your graveyard to place a +1/+1 counter on the Giant. Because the incoming +1/+1 counter immediately annihilates the existing -1/-1 counter through state-based actions, Furystoke Giant is left completely clean of counters and ready to persist all over again endlessly.