Most played cards in Cephalid Breakfast:

2 Decks
Force of Will
8 copies - 4 average
Aether Vial
8 copies - 4 average
Cephalid Illusionist
8 copies - 4 average
Flooded Strand
8 copies - 4 average
Brainstorm
8 copies - 4 average
Stoneforge Mystic
7 copies - 3.5 average
Tundra
6 copies - 3 average
Narcomoeba
6 copies - 3 average
Nomads en-Kor
6 copies - 3 average
Daze
6 copies - 3 average
Cabal Therapy
5 copies - 2.5 average
Eladamri's Call
4 copies - 2 average
Misty Rainforest
4 copies - 2 average
Polluted Delta
4 copies - 2 average
Leyline of the Void
4 copies - 2 average
Recruiter of the Guard
3 copies - 1.5 average
True-Name Nemesis
3 copies - 1.5 average
Dark Confidant
3 copies - 1.5 average
Swords to Plowshares
3 copies - 1.5 average
Underground Sea
3 copies - 1.5 average