Ugin's Nexus + Esoteric Duplicator + Ravenous Intruder

Ugin's Nexus

Esoteric Duplicator

Ravenous Intruder

How it works

1. During your end step, activate Ravenous Intruder by sacrificing Ugin's Nexus.
2. Ugin's Nexus is exiled instead of being put into your graveyard, causing you to take an extra turn after this one.
3. Esoteric Duplicator triggers, causing you to pay 2 to create a token copy of Ugin's Nexus at the beginning of your next end step.
4. Resolve the Ravenous Intruder ability.
5. Move to your extra turn.
6. At the beginning of your end step, Esoteric Duplicator triggers, creating a token copy of Ugin's Nexus.
7. Repeat.