Voltaic Construct + Sceptre of Eternal Glory + Karn, Silver Golem

Voltaic Construct

Sceptre of Eternal Glory

Karn, Silver Golem

How it works

1. Animate Sceptre of Eternal Glory using Karn.
2. Activate Sceptre of Eternal Glory by tapping it, adding three mana of any color
3. Activate Voltaic Construct by paying 2, untapping Sceptre of Eternal Glory.
4. Repeat from step 2.

By bringing Karn, Silver Golem to the table, we gain the crucial ability to animate our noncreature artifacts into artifact creatures. This transforms the Sceptre of Eternal Glory into a legal target for Voltaic Construct's untap ability, circumventing the normal restrictions of being a mana rock. Once the Sceptre can be continuously untamed while producing three mana at the cost of only two to activate the Construct, we are left with a neat net-positive loop that easily generates infinite colored mana.