Scuttling Sliver + Trazyn the Infinite + Runed Stalactite + Grim Monolith

Scuttling Sliver

Trazyn the Infinite

Runed Stalactite

Grim Monolith

How it works

1. Activate Trazyn using Grim Monolith's ability by tapping it, adding CCC
2. Activate Trazyn by paying 2, untapping it.
3. Repeat.

This ingenious loop relies on Trazyn the Infinite absorbing the activated abilities of every artifact in your graveyard thanks to its Prismatic Gallery. By having Grim Monolith sitting in the graveyard, Trazyn gains the ability to tap for three colorless mana, while Scuttling Sliver—granted all creature types by the equipped Runed Stalactite—lends Trazyn its activated ability to untap for just two mana. Because generating three mana and spending two to untap leaves you with a net profit of one colorless mana each cycle, you can easily repeat this process to generate infinite colorless mana.