Derevi, Empyrial Tactician + Faeburrow Elder + Delney, Streetwise Lookout + Phantom Train

Derevi, Empyrial Tactician

Faeburrow Elder

Delney, Streetwise Lookout

Phantom Train

How it works

1. Activate Faeburrow Elder by tapping it, adding at least .
2. Activate Phantom Train by sacrificing Derevi.
3. Choose to return Derevi from your graveyard to the command zone.
4. Resolve the Phantom Train 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 loop transforms the command zone into an infinite mana engine by exploiting Derevi, Empyrial Tactician's unique ability to bypass commander tax. Faeburrow Elder serves as our powerhouse mana producer, generating enough colors to recast Derevi repeatedly, while Phantom Train acts as the convenient sacrifice outlet that sends our commander back where it started. The true catalyst of this loop is Delney, Streetwise Lookout, whose static ability doubles Derevi's entry trigger, allowing a single casting to untap Faeburrow Elder twice and generate a surplus of mana.