Soul Foundry + Corridor Monitor + Gilded Lotus + Primal Vigor

Soul Foundry

Corridor Monitor

Gilded Lotus

Primal Vigor

How it works

1. Activate Gilded Lotus by tapping it, adding three mana of any color.
2. Activate Soul Foundry by paying 2 and tapping it, creating two token copies of Corridor Monitor.
3. When the Corridor Monitor tokens enter the battlefield, they trigger, untapping Soul Foundry and Gilded Lotus.
4. Repeat.

This delightful loop transforms Soul Foundry into an engine for infinite duplication, utilizing Corridor Monitor to constantly refresh your board state each time it enters the battlefield. Because Gilded Lotus is ready to be untapped right alongside the Foundry, you easily generate a surplus of mana on every single iteration to fund the continuous activation costs. To top it all off, Primal Vigor acts as the ultimate catalyst, doubling every single token created so your engine yields an exponential army of Monitors alongside your endless mana.