Most played cards in Grixis Pyromancer:

1 Decks
Lightning Bolt
4 copies - 4 average
Young Pyromancer
4 copies - 4 average
Ponder
4 copies - 4 average
Daze
4 copies - 4 average
Force of Will
4 copies - 4 average
Delver of Secrets
4 copies - 4 average
Brainstorm
4 copies - 4 average
Polluted Delta
4 copies - 4 average
Wasteland
4 copies - 4 average
Volcanic Island
3 copies - 3 average
Underground Sea
3 copies - 3 average
Flooded Strand
3 copies - 3 average
Dread of Night
2 copies - 2 average
True-Name Nemesis
2 copies - 2 average
Diabolic Edict
2 copies - 2 average
Surgical Extraction
2 copies - 2 average
Abrade
2 copies - 2 average
Spell Pierce
2 copies - 2 average
Gurmag Angler
2 copies - 2 average
Thoughtseize
2 copies - 2 average