Karn, the Great Creator + Ugin's Nexus + Throne of Geth + Ichormoon Gauntlet

Karn, the Great Creator

Ugin's Nexus

Throne of Geth

Ichormoon Gauntlet

How it works

1. Activate any other planeswalker by putting zero loyalty counters on it, putting a loyalty counter on Karn.
2. Activate Throne of Geth by tapping it and sacrificing Ugin's Nexus.
3. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
4. Resolve the Throne of Geth ability, putting a loyalty counter on Karn.
5. Activate Karn's second loyalty ability by removing two loyalty counters from it, returning Ugin's Nexus from exile to your hand.
6. Move to your next turn.
7. Cast Ugin's Nexus by paying 5.
8. Repeat.

This ingenious engine hinges on the replacement effect of Ugin's Nexus, which exiles itself to grant you an extra turn whenever it hits your graveyard. By leveraging Throne of Geth to sacrifice the Nexus, you safely trigger its extra turn while sending it directly into exile, where Karn, the Great Creator can easily pluck it right back to your hand using its minus ability. Meanwhile, Ichormoon Gauntlet provides additional utility by letting your planeswalkers proliferate and boosting your spells, creating a seamless loop where you simply recast Ugin's Nexus to take endless extra turns.