Adarkar Valkyrie + Thornbite Staff + Yahenni, Undying Partisan

Adarkar Valkyrie

Thornbite Staff

Yahenni, Undying Partisan

How it works

1. Activate Adarkar Valkyrie by tapping it, targeting another nontoken creature you control.
2. Activate Yahenni by sacrificing the creature targeted in step 1.
3. When the creature dies, Adarkar Valkyrie triggers twice.
4. Resolve the first trigger, untapping Adarkar Valkyrie.
5. Resolve the second trigger, returning the sacrificed creature from your graveyard to the battlefield.
6. Resolve the Yahenni ability.
7. Repeat.

This clever loop centers around Adarkar Valkyrie's targeted death-trigger ability, which marks a creature to return to the battlefield when it dies. By using Yahenni, Undying Partisan to immediately sacrifice that targeted creature, you trigger Adarkar Valkyrie's delayed ability twice—allowing you to return the sacrificed creature while simultaneously untapping the Valkyrie to do it all over again. While Thornbite Staff isn't strictly necessary for the core loop described here, it rests comfortably alongside them in formats like Commander and Legacy, waiting as an alternative engine piece that can grant untapping powers and ping damage whenever creatures perish.