Progenitor Mimic + Warden of the Eye + Time Walk

Progenitor Mimic

Warden of the Eye

Time Walk

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 Warden of the Eye.
3. When the token Warden of the Eye enters the battlefield, it triggers itself, returning Time Walk from your graveyard to your hand.
4. Repeat.