Most played cards in Threshold 5c:

5 Decks
Force of Will
20 copies - 4 average
Swords to Plowshares
20 copies - 4 average
Tarmogoyf
20 copies - 4 average
Flooded Strand
20 copies - 4 average
Polluted Delta
20 copies - 4 average
Counterbalance
20 copies - 4 average
Brainstorm
20 copies - 4 average
Thoughtseize
17 copies - 3.4 average
City of Brass
16 copies - 3.2 average
Sensei's Divining Top
16 copies - 3.2 average
Pyroclasm
16 copies - 3.2 average
Ponder
16 copies - 3.2 average
Nimble Mongoose
16 copies - 3.2 average
Daze
15 copies - 3 average
Krosan Grip
14 copies - 2.8 average
12 copies - 2.4 average
Tundra
10 copies - 2 average
Tropical Island
10 copies - 2 average
Ancient Grudge
8 copies - 1.6 average
Blue Elemental Blast
8 copies - 1.6 average