Most played cards in Merfolk:

1 Decks
Master of the Pearl Trident
4 copies - 4 average
Tide Shaper
4 copies - 4 average
True-Name Nemesis
4 copies - 4 average
Vodalian Hexcatcher
4 copies - 4 average
Wasteland
4 copies - 4 average
Force of Will
4 copies - 4 average
Lord of Atlantis
4 copies - 4 average
Merfolk Trickster
4 copies - 4 average
Cavern of Souls
4 copies - 4 average
Silvergill Adept
4 copies - 4 average
Aether Vial
3 copies - 3 average
Chalice of the Void
3 copies - 3 average
Cursed Totem
2 copies - 2 average
Grafdigger's Cage
2 copies - 2 average
Brazen Borrower
2 copies - 2 average
Submerge
2 copies - 2 average
Dismember
2 copies - 2 average
Chill
1 copies - 1 average
Blue Elemental Blast
1 copies - 1 average
Hurkyl's Recall
1 copies - 1 average