Most played cards in Gush Mentor:

2 Decks
Preordain
8 copies - 4 average
Force of Will
8 copies - 4 average
Flooded Strand
7 copies - 3.5 average
Teferi, Time Raveler
5 copies - 2.5 average
Swords to Plowshares
4 copies - 2 average
Pyroblast
4 copies - 2 average
Snow-Covered Island
4 copies - 2 average
Containment Priest
4 copies - 2 average
Leyline of the Void
4 copies - 2 average
Polluted Delta
4 copies - 2 average
Shattering Spree
4 copies - 2 average
Lavinia, Azorius Renegade
4 copies - 2 average
Tundra
4 copies - 2 average
Scalding Tarn
4 copies - 2 average
Underground Sea
3 copies - 1.5 average
Stony Silence
3 copies - 1.5 average
Snapcaster Mage
3 copies - 1.5 average
Volcanic Island
3 copies - 1.5 average
Surgical Extraction
3 copies - 1.5 average
Energy Flux
2 copies - 1 average