Voltaic Construct + Empowered Autogenerator + Ensoul Artifact

Voltaic Construct

Empowered Autogenerator

Ensoul Artifact

How it works

1. Activate Empowered Autogenerator by tapping it, putting a charge counter on it and adding 1 for each charge counter on it.
2. Activate Voltaic Construct by paying 2, untapping Empowered Autogenerator.
3. Repeat

To pull off this infinite mana loop, you first need to transform Empowered Autogenerator into an artifact creature using Ensoul Artifact, giving it the necessary creature type to be targeted by Voltaic Construct. Once animated, tapping Empowered Autogenerator generates an escalating amount of mana based on its growing stack of charge counters—starting small, but quickly surpassing the cost to untap it. By funneling a portion of that generated mana into Voltaic Construct's activation cost, you can repeatedly ready your primary engine to net as much colored mana as you desire.