Progenitor Mimic + Time Stretch + Timeless Witness

Progenitor Mimic

Time Stretch

Timeless Witness

How it works

1. Cast Time Stretch 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 Timeless Witness.
3. When the token Timeless Witness enters the battlefield, it triggers itself, returning Time Stretch from your graveyard to your hand.
4. Repeat during your second extra turn.