Most played cards in Mono Red Painters:

2 Decks
Magus of the Moon
4 copies - 2 average
Goblin Welder
4 copies - 2 average
Ancient Tomb
4 copies - 2 average
Fable of the Mirror-Breaker
4 copies - 2 average
Leyline of the Void
4 copies - 2 average
Goblin Engineer
4 copies - 2 average
Pyroblast
4 copies - 2 average
Painter's Servant
4 copies - 2 average
Fury
4 copies - 2 average
Urza's Saga
4 copies - 2 average
Lightning Bolt
3 copies - 1.5 average
Mindbreak Trap
3 copies - 1.5 average
Red Elemental Blast
3 copies - 1.5 average
Simian Spirit Guide
3 copies - 1.5 average
Great Furnace
3 copies - 1.5 average
City of Traitors
2 copies - 1 average
Grindstone
2 copies - 1 average
Lotus Petal
2 copies - 1 average
Fiery Confluence
1 copies - 0.5 average
Pithing Needle
1 copies - 0.5 average