Near-infinite colored manaInfinite card drawNear-infinite creature ETBInfinite draw triggersNear-infinite colorless manaNear-infinite creature tokensNear-infinite untap of creatures you controlNear-infinite mana creatures you control can produce
How it works
Activate Karn twice by paying 2, causing Halo Fountain and Chromatic Orrery to become a creature.
Activate Chromatic Orrery by tapping it, adding CCCCC
Activate Halo Fountain's second ability by paying , tapping it, and then untapping it and Chromatic Orrery, causing you to draw a card.