Mirrorpool + Splendid Reclamation + Amulet of Vigor + Coastal Hornclaw

Mirrorpool

Splendid Reclamation

Amulet of Vigor

Coastal Hornclaw

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 Coastal Hornclaw 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, Amulet of Vigor triggers that many times, untapping the lands.
8. Repeat from step 2.

This intricate loop relies on dumping your lands into the graveyard and leveraging Coastal Hornclaw's sacrifice ability to clear the board until only Mirrorpool remains. Once you pay to have Mirrorpool copy the casting of Splendid Reclamation, the resolution floods the battlefield with all those departed lands. This is where Amulet of Vigor does the heavy lifting, its static trigger immediately untapping every single one of those freshly returned lands so you can tap them for mana and start the cycle anew.