Lumra, Bellow of the Woods + Mirrorpool + Zuran Orb + Horizon Explorer

Lumra, Bellow of the Woods

Mirrorpool

Zuran Orb

Horizon Explorer

How it works

1. Activate any number of other lands by tapping them, adding at least 4C.
2. Activate Zuran Orb 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 elegant loop transforms the graveyard into a bottomless reservoir of mana and life. By feeding your own real estate to Zuran Orb, you clear the board down to just Mirrorpool, allowing you to cash in four colorless mana to clone Lumra, Bellow of the Woods and immediately let the legend rule send the copy straight to the graveyard. Each time that token hits the graveyard, its triggered ability fires off to mill four cards and flood the battlefield with every single land you just sacrificed—a process kept entirely smooth and untapped thanks to Horizon Explorer's passive presence on your board.