Sensei's Divining Top + Transplant Theorist + Gran-Gran

Sensei's Divining Top

Transplant Theorist

Gran-Gran

How it works

1. Cast Sensei's Divining Top by paying 0 due to Gran-Gran.
2. When Sensei's Divining Top enters, Transplant Theorist triggers.
3. 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.
4. Resolve the Transplant Theorist trigger, causing you to draw Sensei's Divining Top from your library, and then discard a card other than Sensei's Divining Top.
5. Repeat

This fascinating engine relies on making the usually mana-intensive Sensei's Divining Top entirely free to cast, a feat made possible by the cost-reduction static ability of Gran-Gran when you have enough Lessons in your graveyard. Once you cast the Top for zero mana, Transplant Theorist triggers upon entry to give you a loot effect, but you can respond by tapping the Top to draw a card and place it back on top of your library. When the Transplant Theorist trigger finally resolves, you draw the Top right back out of your library and discard a card, leaving you ready to recast it and repeat the loop indefinitely for infinite card selection and storm count.