Lumra, Bellow of the Woods + Mirrorpool + Need for Speed + Horizon Explorer

Lumra, Bellow of the Woods

Mirrorpool

Need for Speed

Horizon Explorer

How it works

1. Activate any number of other lands by tapping them, adding at least 4C.
2. Activate Need for Speed 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 intricate loop feeds on itself by weaponizing the legend rule through Mirrorpool, using its ability to clone Lumra, Bellow of the Woods while sacrificing the land itself. Each time the token enters the battlefield, its triggered ability mills your library and slams every single land back onto the battlefield, an effect wonderfully accelerated by Horizon Explorer ensuring those lands enter untapped. You can burn through your disposable real estate with Need for Speed to clear the board, ensuring you always have the mana and fodder required to keep the cycle going.