Merfolk
A Modern deck, by Brian Spurlock
19th place at a tournament in Indianapolis, Indiana, United States on 2017-02-25

Maindeck:

Artifacts
4 Aether Vial

Creatures
4 Cursecatcher
3 Harbinger of the Tides
4 Lord of Atlantis (Not currently legal in Modern)
4 Master of the Pearl Trident
4 Master of Waves
3 Merrow Reejerey
4 Silvergill Adept

Enchantments
4 Spreading Seas

Instants
2 Dismember
3 Vapor Snag

Legendary Creatures
1 Kira, Great Glass-Spinner

Basic Lands
10 Island

Lands
2 Cavern of Souls
4 Mutavault
2 Wanderwine Hub

Legendary Lands
1 Minamo, School at Water's Edge
1 Oboro, Palace in the Clouds

Sideboard:
2 Chalice of the Void
1 Grafdigger's Cage
1 Relic of Progenitus
2 Spellskite
2 Tidebinder Mage
1 Dispel
3 Hurkyl's Recall
2 Spell Pierce
1 Kira, Great Glass-Spinner