Toph, the First Metalbender + Ugin's Nexus + Meticulous Excavation + Yahenni, Undying Partisan

Toph, the First Metalbender

Ugin's Nexus

Meticulous Excavation

Yahenni, Undying Partisan

How it works

1. Cast Ugin's Nexus by paying 5.
2. At the beginning of your end step, Toph triggers, causing Ugin's Nexus to become an artifact land creature.
3. Activate Yahenni by sacrificing Ugin's Nexus. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
4. Toph triggers, returning Ugin's Nexus from exile to the battlefield.
5. Resolve the Yahenni ability.
6. Activate Meticulous Excavation by paying 2, returning Ugin's Nexus from the battlefield to your hand.
7. Repeat each turn.

This clever loop relies on Toph, the First Metalbender turning Ugin's Nexus into an artifact land, allowing it to be sacrificed as a creature while ensuring its graveyard-replacement ability triggers appropriately. Once Ugin's Nexus is sent to exile to secure your extra turn, Toph's lingering trigger immediately rescues it back to the battlefield, neatly bypassing its usual finality. From there, Meticulous Excavation returns Ugin's Nexus safely to your hand for just {2}{W} so you can replay it, while Yahenni, Undying Partisan stands ready as the reliable sacrifice outlet to repeat the entire sequence every turn.