Palinchron + Panharmonicon

Palinchron

Panharmonicon

How it works

1. Activate six lands by tapping them, adding at least 4.
2. Cast Palinchron by paying 5.
3. When Palinchron enters the battlefield, it triggers twice.
4. Resolve the first trigger, untapping up to seven lands you control.
5. Activate six lands by tapping them, adding at least 4.
6. Resolve the second Palinchron trigger, untapping up to seven lands you control.
7. Activate Palinchron by paying 2, returning it to your hand from the battlefield.
8. Repeat.

This loop is all about exploiting Palinchron's entry trigger to generate a massive surplus of mana, turning what is normally a self-contained bounce-and-cast engine into an explosive win condition. Ordinarily, Palinchron untaps seven lands when it enters, which doesn't quite generate enough mana on its own to recast it and bounce it again without a discount. However, the presence of Panharmonicon doubles that enter-the-battlefield trigger, giving you two separate untap events that each target up to seven lands. By tapping your lands in response to and between these triggers, you net extra mana with every iteration of the loop, resulting in infinite mana, infinite enters-the-battlefield triggers, and an unbounded storm count.