Merfolk
A Modern deck, by Jonathon Zaczek
2nd place at a tournament in Vancouver, Canada on 2017-02-18

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
1 Tidebinder Mage

Enchantments
4 Spreading Seas

Instants
3 Dismember

Legendary Creatures
2 Vendilion Clique

Basic Lands
12 Island

Lands
2 Cavern of Souls
4 Mutavault

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

Sideboard:
2 Relic of Progenitus
2 Tidebinder Mage
3 Dispel
4 Unified Will
4 Tectonic Edge