Progenitor Mimic + Ardent Elementalist + Notorious Throng

Progenitor Mimic

Ardent Elementalist

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 Ardent Elementalist.
4. When the Ardent Elementalist token enters the battlefield, it triggers, returning Notorious Throng from your graveyard to your hand.
5. Repeat.