Most played cards in Omni-Attack:

1 Decks
Brainstorm
4 copies - 4 average
Cunning Wish
4 copies - 4 average
Force of Will
4 copies - 4 average
Omniscience
4 copies - 4 average
Ponder
4 copies - 4 average
Show and Tell
4 copies - 4 average
Leyline of the Void
4 copies - 4 average
Ancient Tomb
4 copies - 4 average
Flooded Strand
4 copies - 4 average
Pyroclasm
3 copies - 3 average
Sneak Attack
3 copies - 3 average
Preordain
3 copies - 3 average
Lotus Petal
3 copies - 3 average
Polluted Delta
3 copies - 3 average
Boseiju, Who Shelters All
3 copies - 3 average
Volcanic Island
3 copies - 3 average
Emrakul, the Aeons Torn
3 copies - 3 average
Griselbrand
3 copies - 3 average
Echoing Truth
2 copies - 2 average
Firemind's Foresight
2 copies - 2 average