Sensei's Divining Top + Cheering Fanatic + Rook Turret

Sensei's Divining Top

Cheering Fanatic

Rook Turret

How it works

1. Declare Cheering Fanatic as an attacker. When it triggers, choose to name "Sensei's Divining Top".
2. Cast Sensei's Divining Top by paying 0 due to Cheering Fanatic.
3. When Sensei's Divining Top enters, Rook Turret triggers.
4. Holding priority, activate Sensei's Divining Top by tapping it, causing you to draw a card and put Sensei's Divining Top on top of your library.
5. Resolve the Rook Turret trigger, causing you to draw Sensei's Divining Top from your library, and then discard a card other than Sensei's Divining Top.
6. Repeat from step 2

By leveraging Cheering Fanatic to reduce the cost of Sensei's Divining Top to zero, we can cast the artifact for free as often as we like. Every time it enters the battlefield, Rook Turret provides a handy loot effect that cycles through our deck while filling the graveyard. To keep the loop going, we simply tap Sensei's Divining Top in response to the turret's trigger to draw a card and place the top right back onto our library, letting the turret draw it back out so we can recast it.