Mirrorpool + Splendid Reclamation + Overgrown Estate + Tiller Engine

Mirrorpool

Splendid Reclamation

Overgrown Estate

Tiller Engine

How it works

1. Cast Splendid Reclamation by paying 3.
2. Holding priority, activate any number of lands you control except Mirrorpool by tapping them, adding at least 2C.
3. Activate Overgrown Estate by sacrificing a land other than Mirrorpool.
4. Repeat step 3 until Mirrorpool is the only land you control.
5. Activate Mirrorpool's second ability by paying 2C, tapping and sacrificing it, copying Splendid Reclamation.
6. Resolve the Splendid Reclamation copy, returning all land cards from your graveyard to the battlefield tapped.
7. When the lands enter, Tiller Engine triggers that many times, untapping the lands.
8. Repeat from step 2.

This ingenious loop turns a graveyard full of land into an unstoppable, self-sustaining engine of growth. You begin by sacrificing your lands to Overgrown Estate to fuel Mirrorpool's second ability, copying a cast of Splendid Reclamation until only Mirrorpool remains. When that copied Splendid Reclamation resolves, it floods the battlefield with all your fallen lands, immediately waking up Tiller Engine to untap them all and provide the mana needed to repeat the cycle.