Progenitor Mimic + Time Walk + Greenwarden of Murasa

Progenitor Mimic

Time Walk

Greenwarden of Murasa

How it works

1. Cast Time Walk by paying its mana cost, taking an extra turn after this one.
2. At the beginning of your next upkeep, Progenitor Mimic triggers, creating a token copy of Greenwarden of Murasa.
3. When the token Greenwarden of Murasa enters the battlefield, it triggers itself, returning Time Walk from your graveyard to your hand.
4. Repeat.