Most played cards in Rebels:

64 Decks
Swords to Plowshares
256 copies - 4 average
Ramosian Sergeant
246 copies - 3.84 average
Adarkar Wastes
193 copies - 3.02 average
Mother of Runes
179 copies - 2.8 average
Lin Sivvi, Defiant Hero
172 copies - 2.69 average
Mana Leak
163 copies - 2.55 average
Counterspell
154 copies - 2.41 average
Flooded Strand
152 copies - 2.38 average
Defiant Falcon
130 copies - 2.03 average
Disenchant
130 copies - 2.03 average
Whipcorder
113 copies - 1.77 average
Standstill
112 copies - 1.75 average
Meddling Mage
106 copies - 1.66 average
Coastal Tower
103 copies - 1.61 average
Tormod's Crypt
84 copies - 1.31 average
Mishra's Factory
84 copies - 1.31 average
Shared Triumph
79 copies - 1.23 average
Hydroblast
63 copies - 0.98 average
Thermal Glider
56 copies - 0.88 average
Defiant Vanguard
53 copies - 0.83 average