Most played cards in Humans:

3 Decks
Wasteland
12 copies - 4 average
Once Upon a Time
12 copies - 4 average
Champion of the Parish
12 copies - 4 average
Cavern of Souls
12 copies - 4 average
Unclaimed Territory
12 copies - 4 average
Horizon Canopy
12 copies - 4 average
Thalia, Guardian of Thraben
12 copies - 4 average
Surgical Extraction
12 copies - 4 average
Noble Hierarch
12 copies - 4 average
Mayor of Avabruck
11 copies - 3.67 average
Force of Vigor
9 copies - 3 average
Collector Ouphe
9 copies - 3 average
Mana Confluence
7 copies - 2.33 average
Dark Confidant
7 copies - 2.33 average
Thalia's Lieutenant
7 copies - 2.33 average
Sanctum Prelate
6 copies - 2 average
Deafening Silence
6 copies - 2 average
General Kudro of Drannith
6 copies - 2 average
Containment Priest
4 copies - 1.33 average
Kambal, Consul of Allocation
4 copies - 1.33 average