River Kelpie + Thran Vigil + Yahenni, Undying Partisan

River Kelpie

Thran Vigil

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing River Kelpie.
2. When River Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Thran Vigil and River Kelpie trigger.
4. Resolve the Thran Vigil trigger, putting a +1/+1 counter on River Kelpie.
5. Resolve the River Kelpie trigger, causing you to draw a card.
6. Resolve the Yahenni ability
7. Repeat.