Derevi, Empyrial Tactician + Faeburrow Elder + Delney, Streetwise Lookout + Umbral Collar Zealot

Derevi, Empyrial Tactician

Faeburrow Elder

Delney, Streetwise Lookout

Umbral Collar Zealot

How it works

1. Activate Faeburrow Elder by tapping it, adding at least .
2. Activate Umbral Collar Zealot by sacrificing Derevi.
3. Choose to return Derevi from your graveyard to the command zone.
4. Resolve the Umbral Collar Zealot ability
5. Activate Derevi by paying 1, putting it from the command zone onto the battlefield.
6. When Derevi enters the battlefield, it triggers twice.
7. Resolve the first trigger, untapping Faeburrow Elder.
8. Activate Faeburrow Elder by tapping it, adding at least .
9. Resolve the second Derevi trigger, untapping Faeburrow Elder.
10. Repeat.

This clever loop is supercharged by Delney, Streetwise Lookout, whose static ability doubles the enter-the-battlefield trigger of Derevi, Empyrial Tactician because Derevi's power is 2 or less. When you sacrifice Derevi to Umbral Collar Zealot, you can send it right back to the command zone and recast it using the mana generated by Faeburrow Elder. Those doubled Derevi triggers then untap Faeburrow Elder twice, generating a surplus of colored mana while fueling infinite deaths, sacrifices, and surveil triggers.