Voltaic Construct + Thran Forge + Vhal, Candlekeep Researcher

Voltaic Construct

Thran Forge

Vhal, Candlekeep Researcher

How it works

1. Cause Vhal to become an artifact using Thran Forge.
2. Activate Vhal by tapping it, adding at least CCC.
3. Activate Voltaic Construct by paying 2, untapping Vhal.
4. Repeat from step 2.

This brilliant transmutation loop hinges on bending the rules of what an artifact can be, turning Vhal, Candlekeep Researcher into a mechanical powerhouse with the help of Thran Forge. Because Vhal taps to generate colorless mana equal to her toughness—which handily exceeds the cost to untap—Voltaic Construct can continually refresh her at a profit. By funneling that energy back into the Construct's ability, you loop the sequence for an endless supply of colorless mana (though you'll need to find another outlet for it since it can't be spent from your hand) and infinitely untap every artifact creature you control.