Timestream Navigator + Gravecrawler + Fiend Artisan

Timestream Navigator

Gravecrawler

Fiend Artisan

How it works

1. Activate Timestream Navigator by paying 2, tapping it and putting it on the bottom of your library from the battlefield, causing you to take an extra turn after this one.
2. Activate Fiend Artisan by paying 2B/G and sacrificing Gravecrawler, causing you to search your library for Timestream Navigator and put it onto the battlefield.
3. Cast Gravecrawler from your graveyard by paying .
4. Repeat each turn.

This loop lets you seize infinite turns by cycling Timestream Navigator between the battlefield and the bottom of your library. To pull this off, Fiend Artisan acts as your reliable tutor, using its activated ability to sacrifice a creature and fetch the Navigator straight to the battlefield. Meanwhile, Gravecrawler provides the perfect recurring sacrifice fodder for that cost, easily slipping right back out of your graveyard to recast thanks to the Zombie typing shared across the engine.