Tempest Caller

When this creature enters, tap all creatures target opponent controls.

Tempest Harvester

When this creature enters, you get {E}{E} (two energy counters).
{T}, Pay {E}: Draw a card, then discard a card.

Merrow Reejerey

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

Mindspring Merfolk

Exhaust — {X}{U}{U}, {T}: Draw X cards. Put a +1/+1 counter on each Merfolk creature you control. (Activate each exhaust ability only once.)

Kiora, the Rising Tide

When Kiora enters, draw two cards, then discard two cards.
Threshold — Whenever Kiora attacks, if there are seven or more cards in your graveyard, you may create Scion of the Deep, a legendary 8/8 blue Octopus creature token.

Harbinger of the Seas

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.)

Swimmer in Nightmares

This creature gets +3/+0 as long as there are ten or more cards in a single graveyard.
This creature can't be blocked as long as you control an Ashiok planeswalker.

Ink Dissolver

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with this creature, you may reveal it. If you do, each opponent mills three cards.

Moonlit Scavengers

When this creature enters, if you control an artifact or enchantment, return target creature an opponent controls to its owner's hand.

Scroll Thief

Whenever this creature deals combat damage to a player, draw a card.

Gray Harbor Merfolk

This creature can't be blocked.
This creature gets +2/+0 as long as you control a commander that's a creature or planeswalker.

Library Larcenist

Whenever this creature attacks, draw a card.

Svyelun of Sea and Sky

Svyelun has indestructible as long as you control at least two other Merfolk.
Whenever Svyelun attacks, draw a card.
Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Waterwind Scout

Flying
When this creature enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Sage of Fables

Each other Wizard creature you control enters with an additional +1/+1 counter on it.
{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Master of Waves

Protection from red
Elemental creatures you control get +1/+1.
When this creature 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.)

Silvergill Adept

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}.
When this creature enters, draw a card.

True-Name Nemesis

As this creature enters, choose a player.
This creature has protection from the chosen player.

Tidebinder Mage

When this creature 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 this creature.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Rootwater Matriarch

{T}: Gain control of target creature for as long as that creature is enchanted.

Saltwater Stalwart

Whenever this creature deals damage to an opponent, target player draws a card.

Merfolk Coralsmith

{1}: This creature gets +1/-1 until end of turn.
When this creature dies, scry 2.

Halimar Wavewatch

Level up {2} ({2}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-4
0/6
LEVEL 5+
6/6
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Skywatcher Adept

Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying

Thada Adel, Acquisitor

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Thada Adel deals combat damage to a player, search that player's library for an artifact card and exile it. Then that player shuffles. Until end of turn, you may play that card.

Prismwake Merrow

Flash
When this creature enters, target permanent becomes the color or colors of your choice until end of turn.

Merfolk Trickster

Flash
When this creature enters, tap target creature an opponent controls. It loses all abilities until end of turn.

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Merfolk Sovereign

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

Roil Cartographer

Landfall — Whenever a land you control enters, you get {E} (an energy counter).
{T}, Pay six {E}: Draw three cards.

Thieving Skydiver

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When this creature enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to this creature.

Alandra, Sky Dreamer

Whenever you draw your second card each turn, create a 2/2 blue Drake creature token with flying.
Whenever you draw your fifth card each turn, Alandra and Drakes you control each get +X/+X until end of turn, where X is the number of cards in your hand.

Merfolk Wayfinder

Flying
When this creature 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.

Umara Skyfalls

Umara Wizard

Whenever you cast an instant, sorcery, or Wizard spell, this creature gains flying until end of turn.

Umara Wizard // Umara Skyfalls

Simic Fluxmage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{1}{U}, {T}: Move a +1/+1 counter from this creature onto target creature.

Merrow Harbinger

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.

Shaper Apprentice

This creature has flying as long as you control another Merfolk.

Kopala, Warden of Waves

Spells your opponents cast that target a Merfolk you control cost {2} more to cast.
Abilities your opponents activate that target a Merfolk you control cost {2} more to activate.

Seasinger

When you control no Islands, sacrifice this creature.
You may choose not to untap this creature during your untap step.
{T}: Gain control of target creature whose controller controls an Island for as long as you control this creature and this creature remains tapped.

Harbinger of the Tides

You may cast this spell 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.

Attuma, Atlantean Warlord

Other Merfolk you control get +1/+1.
Whenever one or more Merfolk you control attack a player, draw a card.

Herald of Secret Streams

Creatures you control with +1/+1 counters on them can't be blocked.

Vodalian Hexcatcher

Flash
Other Merfolk you control get +1/+1.
Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.

Tishana's Tidebinder

Flash
When this creature enters, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as this creature remains on the battlefield. (Mana abilities can't be targeted.)