My little Merfolk Tribal deck. :3
The idea is to make your creatures stronger and unblockable.
Mainboard:
Spreading Seas: Turns your opponents land into an Island. That's good for three reasons. One, Your opponent, if using a mono deck of another color, now has one less land to use. Two, Some of your creatures give island walk to other Merfolk, making them unblockable. Three, you can draw a card.
Counterspell: Comes in handy sometimes. Especially early when you are still building up your board.
Triton Shorestalker: Cheap early drop and unblockable.
Mist-Cloaked Herald: Cheap early drop and unblockable.
Master of the Pearl Trident: Gives other Merfolk you controll +1/+1 and island walk.
Lord of Atlantis: Gives all Merfolk islandwalk and +1/+1. Basically a better Master of the card:Pearl Trident.
Silvergill Adept: Two Power and you can draw a card.
Vodalian Hexcatcher: Can be played at any time. Gives other Merfolk +1/+1 and you can now sacrifice a Merfolk to counter a noncreature spell.
Aether Vial: Aether Vial doesn't cost much and lets you play your creatures for free. That speeds up the process of filling your board with creatures.
Tide Shaper: Tide Shaper is quite cheap and let's you turn your opponents lands into islands as long as Tide Shaper is on the board, just like the Spreading Seas. Tide Shaper also gains +1/+1 as long as your opponent controls an Island.
Svyelun of Sea and Sky: Becomes indestructible if you have at least two other Merfolk on you board. When they attack you can draw a card. They also give other Merfolk Ward 1, that helps protecting your other creatures.
Maybeboard:
Merfolk Sovereign: Gives other Merfolk +1/+1. You can also tap it in order to make a target merfolk unblockable for one turn.
Merrow Reejerey: Gives other Merfolk +1/+1 and when you cast a Merfolk spell you can tap or untap a target permanent.
I hope you will enjoy this deck as much as I have. ^^
Feel free to give suggestions. I am always happy to learn about new cards. :)
Change 1: After asking in the forum what I could do against Mono Black Vampire Aggro made by KingJellyfish, wallisface recomended to raise the amount of land from 19 to 22. They also recommended to use Aether Vial and Tide Shaper. They told me that Merfolk Sovereign is probably the weakest card in the deck. I tested their recommendations and found it to be more effective. Thanks to wallisface for the help!