Most played cards in Mono Black Aggro:

5 Decks
Ravenous Rats
20 copies - 4 average
Chittering Rats
20 copies - 4 average
Distress
17 copies - 3.4 average
Blinkmoth Nexus
16 copies - 3.2 average
Aether Vial
16 copies - 3.2 average
Cranial Extraction
15 copies - 3 average
Nezumi Graverobber
14 copies - 2.8 average
Pithing Needle
14 copies - 2.8 average
Nekrataal
13 copies - 2.6 average
Umezawa's Jitte
12 copies - 2.4 average
Skull Collector
12 copies - 2.4 average
Sun Droplet
11 copies - 2.2 average
Skullsnatcher
11 copies - 2.2 average
Echoing Decay
10 copies - 2 average
Rend Flesh
9 copies - 1.8 average
9 copies - 1.8 average
Terror
9 copies - 1.8 average
Ink-Eyes, Servant of Oni
8 copies - 1.6 average
Tomb of Urami
5 copies - 1 average
Lose Hope
4 copies - 0.8 average