Toph, the First Metalbender + Phyrexian Altar + Mycosynth Lattice

Toph, the First Metalbender

Phyrexian Altar

Mycosynth Lattice

How it works

1. Cast the earthbending creature by paying its mana cost, causing it to enter as an artifact land creature due to Mycosynth Lattice and Toph.
2. When that creature enters, it earthbends, causing itself to become a land creature with haste, putting at least one +1/+1 counter on itself, and creating a delayed triggered ability.
3. Activate Phyrexian Altar by sacrificing that creature, adding one mana.
4. When that creature dies, the delayed ability from step 2 triggers, causing it to return to the battlefield tapped as an artifact land creature.
5. Repeat from step 2 any number of times.