Most played cards in Stax:

3 Decks
Smokestack
12 copies - 4 average
Goblin Welder
12 copies - 4 average
Mishra's Workshop
12 copies - 4 average
Tangle Wire
12 copies - 4 average
Sphere of Resistance
12 copies - 4 average
Volcanic Island
12 copies - 4 average
Polluted Delta
11 copies - 3.67 average
Red Elemental Blast
10 copies - 3.33 average
Blood Moon
9 copies - 3 average
Rack and Ruin
8 copies - 2.67 average
Meditate
7 copies - 2.33 average
Tormod's Crypt
6 copies - 2 average
Fire // Ice
5 copies - 1.67 average
Overload
5 copies - 1.67 average
Triskelion
4 copies - 1.33 average
Karn, Silver Golem
4 copies - 1.33 average
Sol Ring
3 copies - 1 average
Badlands
3 copies - 1 average
Tolarian Academy
3 copies - 1 average
Strip Mine
3 copies - 1 average