Scouring Swarm + Beifong's Bounty Hunters + Umbral Collar Zealot

Scouring Swarm

Beifong's Bounty Hunters

Umbral Collar Zealot

How it works

1. Activate Umbral Collar Zealot by sacrificing another nonland creature you control.
2. When the creature dies, Beifong's Bounty Hunters triggers, earthbending a land you control.
3. Resolve the Umbral Collar Zealot ability.
4. Activate Umbral Collar Zealot by sacrificing the earthbent land.
5. When the land dies, it and Scouring Swarm trigger.
6. Resolve the land's trigger, returning it from your graveyard to the battlefield tapped.
7. Resolve the Scouring Swarm trigger, untapping it and creating a creature token.
8. Resolve the Umbral Collar Zealot ability.
9. Repeat.