Mirrorpool + Splendid Reclamation + Lithatog + Spelunking

Mirrorpool

Splendid Reclamation

Lithatog

Spelunking

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 Lithatog 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 untapped due to Spelunking.
7. Repeat from step 2.

This clever loop harnesses the mass-reanimation power of Splendid Reclamation to repeatedly sweep your graveyard clean and flood your battlefield with lands. The key to keeping the engine running smoothly is Spelunking, whose passive ability ensures every single returned land enters untapped and ready to generate mana immediately. Meanwhile, Lithatog acts as the necessary sacrifice outlet to send your lands straight to the graveyard, while Mirrorpool provides the ultimate payoff by sacrificing itself to copy the initial Splendid Reclamation spell over and over again.