Most played cards in Threshold:

1 Decks
Swords to Plowshares
4 copies - 4 average
Nimble Mongoose
4 copies - 4 average
Tropical Island
4 copies - 4 average
Tundra
4 copies - 4 average
Wasteland
4 copies - 4 average
Meddling Mage
4 copies - 4 average
Polluted Delta
4 copies - 4 average
Brainstorm
4 copies - 4 average
Daze
4 copies - 4 average
Force of Will
4 copies - 4 average
Energy Flux
3 copies - 3 average
Chill
3 copies - 3 average
Werebear
3 copies - 3 average
Engineered Explosives
3 copies - 3 average
Stifle
3 copies - 3 average
Null Rod
3 copies - 3 average
Ray of Revelation
3 copies - 3 average
Ground Seal
3 copies - 3 average
Mental Note
2 copies - 2 average
Flooded Strand
2 copies - 2 average