Beifong's Bounty Hunters + Gravecrawler + Umbral Collar Zealot + Amulet of Vigor

Beifong's Bounty Hunters

Gravecrawler

Umbral Collar Zealot

Amulet of Vigor

How it works

1. Activate Umbral Collar Zealot by sacrificing Gravecrawler.
2. When Gravecrawler dies, Beifong's Bounty Hunters triggers, earthbending a land that can tap to produce at least .
3. Resolve the Umbral Collar Zealot ability.
4. Activate Umbral Collar Zealot by sacrificing the land.
5. When the land dies, Beifong's Bounty Hunters triggers, returning the land from your graveyard to the battlefield tapped.
6. When the land enters, Amulet of Vigor triggers, untapping the land.
7. Resolve the Umbral Collar Zealot ability.
8. Activate the land by tapping it, adding at least .
9. Cast Gravecrawler from your graveyard by paying .
10. Repeat.