Jin-Gitaxias, Progress Tyrant + Ugin's Nexus + Master Transmuter

Jin-Gitaxias, Progress Tyrant

Ugin's Nexus

Master Transmuter

How it works

1. Cast Ugin's Nexus by paying 5.
2. Jin-Gitaxias triggers, copying the Ugin's Nexus spell.
3. Resolve the copied Ugin's Nexus.
4. Resolve the Ugin's Nexus from step 1, exiling the token copy of Ugin's Nexus due to the legend rule and taking an extra turn after this one.
5. Activate Master Transmuter by paying , tapping it, and returning Ugin's Nexus to your hand, choosing not to put an artifact card from your hand onto the battlefield.
6. Repeat each turn.