Progenitor Mimic + Shipwreck Dowser + Notorious Throng

Progenitor Mimic

Shipwreck Dowser

Notorious Throng

How it works

1. Deal combat damage to an opponent using a Rogue.
2. Cast Notorious Throng for its prowl cost by paying 5, causing you to take an extra turn after this one.
3. At the beginning of your next upkeep, Progenitor Mimic triggers, creating a token copy of Shipwreck Dowser.
4. When the Shipwreck Dowser token enters the battlefield, it triggers, returning Notorious Throng from your graveyard to your hand.
5. Repeat.