Ashaya, Soul of the Wild + Celestial Dawn + Emeria Shepherd + Yahenni, Undying Partisan

Ashaya, Soul of the Wild

Celestial Dawn

Emeria Shepherd

Yahenni, Undying Partisan

How it works

1. Cast any creature by paying its mana cost.
2. When the creature enters as a Plains due to Ashaya and Emeria Shepherd, Emeria Shepherd triggers.
3. Holding priority, activate Yahenni by sacrificing the creature cast in step 1.
4. Resolve the Emeria Shepherd trigger, returning another creature from your graveyard to the battlefield.
5. Repeat from step 2.

This engine transforms the battlefield into a recursive loop by turning every creature into a literal land through Ashaya, Soul of the Wild. Because Celestial Dawn ensures all your lands are Plains, every creature you cast triggers Emeria Shepherd's landfall ability straight to the battlefield rather than just your hand. To keep the loop going, you simply sacrifice that creature to Yahenni, Undying Partisan, which not only fuels death triggers and protects itself with indestructible, but also feeds the very graveyard that Emeria Shepherd mines to pull back your next threat.