Sensei's Divining Top + Cloud Key + Fateful Discovery

Sensei's Divining Top

Cloud Key

Fateful Discovery

How it works

1. Cast Sensei's Divining Top by paying 0 due to Cloud Key.
2. When Sensei's Divining Top enters, Fateful Discovery 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 Fateful Discovery trigger, causing you to draw Sensei's Divining Top from your library.
5. Repeat

This clever loop turns your library into a bottomless well by exploiting the interaction between a top-decking artifact and a cost reducer. With Cloud Key set to artifacts, Sensei's Divining Top becomes completely free to cast, meaning you can deploy it over and over again without draining your mana. Every time it enters the battlefield, Fateful Discovery triggers to draw you a card, letting you respond by tapping Sensei's Divining Top to draw a card and slide it back onto the top of your library just in time for Fateful Discovery to draw it right back out.