Merfolk
A Modern deck, by Cristo Yanez
10th place at a StarCityGames.com Invitational tournament in Washington, District of Columbia on 2015-01-25

Maindeck:

Artifacts
4 Aether Vial

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

Enchantments
3 Spreading Seas

Instants
3 Path to Exile

Legendary Creatures
2 Kira, Great Glass-Spinner
3 Thalia, Guardian of Thraben

Legendary Enchantment Creatures
1 Thassa, God of the Sea

Basic Lands
4 Island

Lands
4 Hallowed Fountain
4 Mutavault
4 Seachrome Coast
4 Wanderwine Hub

Sideboard:
1 Grafdigger's Cage
1 Relic of Progenitus
2 Hushwing Gryff
1 Tidebinder Mage
2 Rest in Peace
2 Hurkyl's Recall
2 Spell Pierce
2 Swan Song
2 Kataki, War's Wage