Progenitor Mimic + Shipwreck Dowser + Walk the Aeons

Progenitor Mimic

Shipwreck Dowser

Walk the Aeons

How it works

1. Cast Walk the Aeons 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 Shipwreck Dowser.
3. When the token Shipwreck Dowser enters the battlefield, it triggers itself, returning Walk the Aeons from your graveyard to your hand.
4. Repeat.