Claustrophobia

Enchant creature
When Claustrophobia enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Tidal Warrior

{T}: Target land becomes an Island until end of turn.

Tidebinder Mage

When Tidebinder Mage enters, tap target red or green creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Tidebinder Mage.

Blighted Cataract

{T}: Add {C}.
{5}{U}, {T}, Sacrifice Blighted Cataract: Draw two cards.

Aquitect's Will

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Concentrate

Cleaver Riot

Creatures you control gain double strike until end of turn. (They deal both first-strike and regular combat damage.)

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Master of the Pearl Trident

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Battle Squadron

Flying
Battle Squadron's power and toughness are each equal to the number of creatures you control.

Goblin Diplomats

{T}: Each creature attacks this turn if able.

Merfolk Looter

Harbinger of the Tides

You may cast this card as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

Island

Brittle Effigy

{4}, {T}, Exile Brittle Effigy: Exile target creature.

Streambed Aquitects

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)
{T}: Target land becomes an Island until end of turn.

Boggart Brute

Menace (This creature can't be blocked except by two or more creatures.)

Tarfire

Wake Thrasher

Whenever a permanent you control becomes untapped, Wake Thrasher gets +1/+1 until end of turn.

Goblin Chieftain

Haste (This creature can attack and {T} as soon as it comes under your control.)
Other Goblin creatures you control get +1/+1 and have haste.

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Goblin Glory Chaser

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
As long as Goblin Glory Chaser is renowned, it has menace. (It can't be blocked except by two or more creatures.)

Foundry Street Denizen

Whenever another red creature you control enters, Foundry Street Denizen gets +1/+0 until end of turn.

Merrow Reejerey

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Mountain

Gempalm Incinerator

Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)
When you cycle Gempalm Incinerator, you may have it deal X damage to target creature, where X is the number of Goblins on the battlefield.

Scroll Thief

Whenever Scroll Thief deals combat damage to a player, draw a card.

Goblin Razerunners

{1}{R}, Sacrifice a land: Put a +1/+1 counter on Goblin Razerunners.
At the beginning of your end step, you may have Goblin Razerunners deal damage equal to the number of +1/+1 counters on it to target player or planeswalker.

Misdirection

You may exile a blue card from your hand rather than pay this spell's mana cost.
Change the target of target spell with a single target.

Cold-Eyed Selkie

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Cold-Eyed Selkie deals combat damage to a player, you may draw that many cards.

Merfolk Sovereign

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Master of Waves

Protection from red
Elemental creatures you control get +1/+1.
When Master of Waves enters, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Goblin Wardriver

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Brute Strength

Target creature gets +3/+1 and gains trample until end of turn. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.

Inkfathom Divers

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
When Inkfathom Divers enters, look at the top four cards of your library, then put them back in any order.

Tidal Wave

Create a 5/5 blue Wall creature token with defender. Sacrifice it at the beginning of the next end step.

Goblin Grenade

As an additional cost to cast this spell, sacrifice a Goblin.
Goblin Grenade deals 5 damage to any target.

Tidal Courier

When Tidal Courier enters, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.
{3}{U}: Tidal Courier gains flying until end of turn.

Goblin Rabblemaster

Other Goblin creatures you control attack each combat if able.
At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste.
Whenever Goblin Rabblemaster attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Goblin Charbelcher

{3}, {T}: Reveal cards from the top of your library until you reveal a land card. Goblin Charbelcher deals damage equal to the number of nonland cards revealed this way to any target. If the revealed land card was a Mountain, Goblin Charbelcher deals double that damage instead. Put the revealed cards on the bottom of your library in any order.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Goblin Ringleader

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Goblin Ringleader enters, reveal the top four cards of your library. Put all Goblin cards revealed this way into your hand and the rest on the bottom of your library in any order.

Mind Spring

Goblin Goon

Goblin Goon can't attack unless you control more creatures than defending player.
Goblin Goon can't block unless you control more creatures than attacking player.

Triton Tactics

Up to two target creatures each get +0/+3 until end of turn. Untap those creatures. At this turn's next end of combat, tap each creature that was blocked by one of those creatures this turn and it doesn't untap during its controller's next untap step.

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

Goblin Tunneler

{T}: Target creature with power 2 or less can't be blocked this turn.

Ember Hauler

{1}, Sacrifice Ember Hauler: It deals 2 damage to any target.

Blighted Gorge

{T}: Add {C}.
{4}{R}, {T}, Sacrifice Blighted Gorge: It deals 2 damage to any target.

Essence Scatter

Rootwater Hunter

{T}: Rootwater Hunter deals 1 damage to any target.

Warren Instigator

Double strike
Whenever Warren Instigator deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield.

Merfolk Wayfinder

Flying
When Merfolk Wayfinder enters, reveal the top three cards of your library. Put all Island cards revealed this way into your hand and the rest on the bottom of your library in any order.