Most played cards in Threshold:

3 Decks
Mental Note
11 copies - 3.67 average
Spell Snare
9 copies - 3 average
Tarmogoyf
8 copies - 2.67 average
Nimble Mongoose
8 copies - 2.67 average
Polluted Delta
7 copies - 2.33 average
Counterspell
7 copies - 2.33 average
Smother
7 copies - 2.33 average
Ghastly Demise
6 copies - 2 average
Flooded Strand
6 copies - 2 average
Tormod's Crypt
5 copies - 1.67 average
5 copies - 1.67 average
Aether Burst
4 copies - 1.33 average
Memory Lapse
4 copies - 1.33 average
Duress
4 copies - 1.33 average
Watery Grave
4 copies - 1.33 average
Careful Study
4 copies - 1.33 average
Basking Rootwalla
4 copies - 1.33 average
Breeding Pool
4 copies - 1.33 average
Leyline of the Void
4 copies - 1.33 average
Werebear
4 copies - 1.33 average