Most played cards in Merfolks:

3 Decks
Wasteland
12 copies - 4 average
Force of Will
12 copies - 4 average
Lord of Atlantis
12 copies - 4 average
Cursecatcher
12 copies - 4 average
Merrow Reejerey
11 copies - 3.67 average
Silvergill Adept
11 copies - 3.67 average
Daze
10 copies - 3.33 average
Null Rod
10 copies - 3.33 average
Stifle
9 copies - 3 average
Umezawa's Jitte
7 copies - 2.33 average
Mutavault
6 copies - 2 average
Energy Flux
6 copies - 2 average
Polluted Delta
6 copies - 2 average
Hurkyl's Recall
6 copies - 2 average
Flooded Strand
5 copies - 1.67 average
Aether Spellbomb
4 copies - 1.33 average
Relic of Progenitus
4 copies - 1.33 average
Spellstutter Sprite
4 copies - 1.33 average
Pithing Needle
4 copies - 1.33 average
Echoing Truth
3 copies - 1 average