Most played cards in Goblins:

2 Decks
Goblin Recruiter
8 copies - 4 average
Thalia, Guardian of Thraben
8 copies - 4 average
Duress
8 copies - 4 average
Pyroblast
8 copies - 4 average
Wasteland
8 copies - 4 average
Once Upon a Time
8 copies - 4 average
Cavern of Souls
8 copies - 4 average
Wooded Foothills
7 copies - 3.5 average
Ravenous Trap
6 copies - 3 average
Containment Priest
6 copies - 3 average
Kataki, War's Wage
5 copies - 2.5 average
Badlands
4 copies - 2 average
Plateau
4 copies - 2 average
By Force
3 copies - 1.5 average
Wear // Tear
3 copies - 1.5 average
Deafening Silence
3 copies - 1.5 average
Path to Exile
3 copies - 1.5 average
Mox Jet
2 copies - 1 average
Mox Pearl
2 copies - 1 average
Mox Ruby
2 copies - 1 average