Soulherder + Eternal Witness + Time Warp

Soulherder

Eternal Witness

Time Warp

How it works

1. With Soulherder and a creature based spell recursion effect on the battlefield, cast the extra turn spell.
2. Move to end step and target the creature with Soulherder's ability.
3. When creature re-enters the battlefield, target the extra turn spell in your graveyard and return it to your hand, then pass to yourself.
4. Repeat