Most played cards in Junk:

5 Decks
Brainstorm
20 copies – 4 avg
Force of Will
20 copies – 4 avg
Ponder
20 copies – 4 avg
Wasteland
15 copies – 3 avg
Polluted Delta
15 copies – 3 avg
Force of Negation
13 copies – 2.6 avg
Underground Sea
13 copies – 2.6 avg
Dragon's Rage Channeler
12 copies – 2.4 avg
Orcish Bowmasters
12 copies – 2.4 avg
Daze
12 copies – 2.4 avg
Murktide Regent
11 copies – 2.2 avg
Pyroblast
11 copies – 2.2 avg
Volcanic Island
10 copies – 2 avg
Lightning Bolt
10 copies – 2 avg
Mishra's Bauble
10 copies – 2 avg
Flooded Strand
9 copies – 1.8 avg
Psychic Frog
8 copies – 1.6 avg
Tamiyo, Inquisitive Student
8 copies – 1.6 avg
Misty Rainforest
7 copies – 1.4 avg
Surgical Extraction
7 copies – 1.4 avg