Restless Apparition + Thran Vigil + Yahenni, Undying Partisan

Restless Apparition

Thran Vigil

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing Restless Apparition.
2. When Restless Apparition 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 Restless Apparition.
4. Resolve the Yahenni ability.
5. Repeat.