Vigean Graftmage + Chromatic Orrery + Karn, the Great Creator

Vigean Graftmage

Chromatic Orrery

Karn, the Great Creator

How it works

1. Activate Karn's first ability by putting a loyalty counter on it, causing Chromatic Orrery to become an artifact creature until end of turn.
2. Activate Chromatic Orrery's first ability by tapping it, adding 5.
3. Activate Vigean Graftmage by paying 2, untapping Chromatic Orrery.
4. Repeat from step 2.
5. Once you have infinite mana, you may activate Chromatic Orrery's second ability instead to draw infinite cards.