Voltaic Construct + Neurok Transmuter + Rainveil Rejuvenator

Voltaic Construct

Neurok Transmuter

Rainveil Rejuvenator

How it works

1. Cause Rainveil Rejuvenator to become an artifact using Neurok Transmuter.
2. Activate Rainveil Rejuvenator by tapping it, adding at least .
3. Activate Voltaic Construct by paying 2, untapping Rainveil Rejuvenator.
4. Repeat from step 2.

By turning Rainveil Rejuvenator into an artifact with Neurok Transmuter's first ability, you cleverly bypass its standard limitations and turn it into a valid target for Voltaic Construct. Once that transformation is complete, tapping Rainveil Rejuvenator generates green mana based on its power, which easily funds the two mana required by Voltaic Construct to untap it. As long as you have enough green mana available to start the loop, this mechanical marriage yields infinite green mana and infinite untaps for your artifact creatures.