Lumra, Bellow of the Woods + Mirrorpool + Lithatog + Horizon Explorer

Lumra, Bellow of the Woods

Mirrorpool

Lithatog

Horizon Explorer

How it works

1. Activate any number of other lands by tapping them, adding at least 4C.
2. Activate Lithatog by sacrificing a land except Mirrorpool.
3. Repeat step 2 until you control no lands except Mirrorpool.
4. Activate Mirrorpool's third ability by paying 4C, tapping and sacrificing it, creating a token copy of Lumra.
5. Put the Lumra token into your graveyard due to the legend rule.
6. The Lumra token's enters-the-battlefield ability triggers, causing you to mill four cards and return all land cards from your graveyard to the battlefield untapped due to Horizon Explorer.
7. Repeat.

This brilliant loop transforms Mirrorpool into a relentless engine of resurrection by exploiting the sheer scale of Lumra, Bellow of the Woods. By feeding your own lands to Lithatog, you strip your board down until only Mirrorpool remains, allowing you to pay its steep cost to clone Lumra and immediately sacrifice the original to the legend rule. Every time the token enters the battlefield, its trigger floods your graveyard with milled cards and sweeps every single land straight back onto the battlefield—an onslaught smoothly accelerated by Horizon Explorer ensuring those returning lands enter untapped to fuel your mana once more.