Most played cards in Burn:

2 Decks
Red Elemental Blast
8 copies - 4 average
Lightning Bolt
8 copies - 4 average
Chain Lightning
8 copies - 4 average
Earthquake
7 copies - 3.5 average
Fireball
6 copies - 3 average
Stone Rain
6 copies - 3 average
Disintegrate
5 copies - 2.5 average
Mana Flare
4 copies - 2 average
Blood Moon
4 copies - 2 average
Plateau
4 copies - 2 average
Urza's Power Plant
4 copies - 2 average
Urza's Mine
4 copies - 2 average
Rukh Egg
4 copies - 2 average
Flashfires
4 copies - 2 average
Mishra's Factory
4 copies - 2 average
Uthden Troll
4 copies - 2 average
Nevinyrral's Disk
4 copies - 2 average
Urza's Tower
4 copies - 2 average
Wall of Dust
3 copies - 1.5 average
Equinox
3 copies - 1.5 average