River Song + Conjurer's Bauble + Prototype Portal + Notorious Throng

River Song

Conjurer's Bauble

Prototype Portal

Notorious Throng

How it works

1. Activate Prototype Portal by paying 1 and tapping it, creating a token copy of Conjurer's Bauble.
2. Deal combat damage to an opponent using a Rogue.
3. Cast Notorious Throng for its prowl cost by paying 5, causing you to take an extra turn after this one.
4. Activate the Conjurer's Bauble token by tapping and sacrificing it, putting Notorious Throng onto the bottom of your library from your graveyard, and then causing you to draw Notorious Throng from the bottom of your library due to River Song.
5. Repeat each turn.