Steelswarm Operator + Agatha's Soul Cauldron + Soliton

Steelswarm Operator

Agatha's Soul Cauldron

Soliton

How it works

1. Activate Steelswarm Operator's second ability by tapping it, adding that can only be spent to activate abilities of artifacts.
2. Activate Steelswarm Operator using Soliton's ability by paying , untapping it.
3. Repeat.

This clever setup hinges on Agatha's Soul Cauldron granting the activated ability of Soliton to Steelswarm Operator, allowing the latter to untap itself for just one mana. Because Agatha's Soul Cauldron also allows you to spend mana as though it were any color for activated abilities, the restricted blue mana generated by Steelswarm Operator's second ability can be fed right back into that untap cost. The result is an infinite loop that yields boundless blue mana for artifact spells and artifact abilities alike, all while keeping your engine entirely self-contained.