Most played cards in Grenzo, Havoc Raiser:

2 Decks
Smash to Smithereens
2 copies - 1 average
Smuggler's Copter
2 copies - 1 average
Molten Rain
2 copies - 1 average
Rolling Earthquake
2 copies - 1 average
Incinerate
2 copies - 1 average
Skullclamp
2 copies - 1 average
Sin Prodder
2 copies - 1 average
Collective Defiance
2 copies - 1 average
Lightning Bolt
2 copies - 1 average
Sudden Demise
2 copies - 1 average
Ruination
2 copies - 1 average
Bloodstained Mire
2 copies - 1 average
Cavern of Souls
2 copies - 1 average
Smoldering Crater
2 copies - 1 average
Forgotten Cave
2 copies - 1 average
Wooded Foothills
2 copies - 1 average
Arid Mesa
2 copies - 1 average
Stormbreath Dragon
2 copies - 1 average
Chandra, Torch of Defiance
2 copies - 1 average
Exquisite Firecraft
2 copies - 1 average