Voltaic Construct + Mycosynth Lattice + Incubation Druid

Voltaic Construct

Mycosynth Lattice

Incubation Druid

How it works

1. Activate Incubation Druid by tapping it, adding three mana of any type a land you control can produce
2. Activate Voltaic Construct by paying 2, untapping Incubation Druid.
3. Repeat

This loop relies on Mycosynth Lattice to transform every single permanent on the battlefield into an artifact, crucially turning Incubation Druid into an artifact creature. Because Incubation Druid now counts as an artifact, it can be repeatedly untrapped by Voltaic Construct's ability for a cost of {2}. As long as Incubation Druid has a +1/+1 counter to fuel its tap for three mana, this exchange yields a net positive of one mana per iteration, successfully generating infinite mana of any type your lands can produce.