Mirrorpool + Splendid Reclamation + Thaumatog + Archelos, Lagoon Mystic

Mirrorpool

Splendid Reclamation

Thaumatog

Archelos, Lagoon Mystic

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 Thaumatog 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 Archelos.
7. Repeat from step 2.

This intricate loop transforms a graveyard full of lands into a self-sustaining engine by cleverly manipulating the battlefield and stack. You begin by feeding your own real estate to Thaumatog, sacrificing your lands one by one until Mirrorpool stands alone as your sole remaining land. With enough mana floated to activate Mirrorpool, you sacrifice it to copy the very Splendid Reclamation you cast, which then floods the battlefield with all those lands you just sacrificed. Because Archelos, Lagoon Mystic is kept untapped during the resolution, every single one of those returning lands enters the battlefield completely untethered from the usual restriction of entering tapped, ready to be tapped for mana and sacrificed all over again.