Most played cards in Captain America:

4 Decks
Lightning Angel
16 copies - 4 average
Prismatic Lens
16 copies - 4 average
Temporal Isolation
16 copies - 4 average
Terramorphic Expanse
16 copies - 4 average
Foresee
10 copies - 2.5 average
Aven Riftwatcher
9 copies - 2.25 average
Detritivore
9 copies - 2.25 average
Nimbus Maze
9 copies - 2.25 average
Boom // Bust
8 copies - 2 average
Flagstones of Trokair
8 copies - 2 average
Venser, Shaper Savant
8 copies - 2 average
Sunlance
8 copies - 2 average
Momentary Blink
8 copies - 2 average
Serra Avenger
8 copies - 2 average
Riftwing Cloudskate
8 copies - 2 average
Cancel
8 copies - 2 average
6 copies - 1.5 average
Numot, the Devastator
6 copies - 1.5 average
Vesuvan Shapeshifter
6 copies - 1.5 average
Dawn Charm
4 copies - 1 average