Chromatic Orrery + Umbral Mantle + Karn's Touch

Chromatic Orrery

Umbral Mantle

Karn's Touch

How it works

1. Activate Chromatic Orrery's first ability by tapping it, adding 5.
2. Cast Karn's Touch by paying 2, causing Chromatic Orrery to become an artifact creature until end of turn.
3. Activate Umbral Mantle's equip ability by paying 0, attaching it to Chromatic Orrery.
4. Activate Chromatic Orrery by paying 3 and untapping it, giving it +2/+2 until end of turn.
5. Activate Chromatic Orrery's first ability by tapping it, adding 5.
6. Repeat from step 4.
7. Once you have infinite mana, you may instead use Chromatic Orrery's second ability if you control a colored permanent.

By animating Chromatic Orrery into an artifact creature with Karn's Touch, we open the door to attaching Umbral Mantle for free. Because tapping the Orrery yields five mana while the Mantle's untap ability only costs three, you easily generate infinite colorless mana with a surplus left over on every cycle. Furthermore, Chromatic Orrery's own passive ability ensures that this raw colorless energy can be spent as mana of any color, letting you completely filter and leverage your infinite pool to fuel its card-drawing activation.