Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Drag Under

Return target creature to its owner's hand.
Draw a card.

Island

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Blink of an Eye

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.

Grow from the Ashes

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Search your library for a basic land card, put it onto the battlefield, then shuffle. If this spell was kicked, instead search your library for two basic land cards, put them onto the battlefield, then shuffle.

Coral Commando

Towering-Wave Mystic

Whenever this creature deals damage, target player mills that many cards.

Divination

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Darting Merfolk

{U}: Return this creature to its owner's hand.

Cancel

Temur Runemark

Enchant creature
Enchanted creature gets +2/+2.
Enchanted creature has trample as long as you control a blue or red permanent.

Merfolk Skydiver

Flying
When this creature enters, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Kiora's Follower

Coralhelm Guide

{4}{U}: Target creature can't be blocked this turn.

Thornwood Falls

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {U}.

Nullify

Triton Shorethief

Dakra Mystic

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.

Strength in Numbers

Until end of turn, target creature gains trample and gets +X/+X, where X is the number of attacking creatures.

Jade Guardian

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
When this creature enters, put a +1/+1 counter on target Merfolk you control.

Naturalize

Rootwater Hunter

{T}: This creature deals 1 damage to any target.

Salvager of Secrets

When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Deeproot Warrior

Whenever this creature becomes blocked, it gets +1/+1 until end of turn.

Headwater Sentries

Triton Shorestalker

Prophetic Prism

When this artifact enters, draw a card.
{1}, {T}: Add one mana of any color.

Hydroform

Target land becomes a 3/3 Elemental creature with flying until end of turn. It's still a land.

Tishana's Wayfinder

When this creature enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Deepwater Hypnotist

Inspired — Whenever this creature becomes untapped, target creature an opponent controls gets -3/-0 until end of turn.

Wavecrash Triton

Heroic — Whenever you cast a spell that targets this creature, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Watertrap Weaver

When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Implement of Examination

{U}, Sacrifice this artifact: Draw a card.
When this artifact is put into a graveyard from the battlefield, draw a card.

Deeproot Waters

Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Metathran Soldier

Verdant Haven

Enchant land
When this Aura enters, you gain 2 life.
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Augur of Bolas

When this creature enters, look at the top three cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Tatyova, Benthic Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Jungle Delver

{3}{G}: Put a +1/+1 counter on this creature.

Shaper Apprentice

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

Simic Keyrune

{T}: Add {G} or {U}.
{G}{U}: This artifact becomes a 2/3 green and blue Crab artifact creature with hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Compelling Argument

Target player mills five cards.
Cycling {U} ({U}, Discard this card: Draw a card.)

Blinding Fog

Prevent all damage that would be dealt to creatures this turn. Creatures you control gain hexproof until end of turn. (They can't be the targets of spells or abilities your opponents control.)

Karametra's Favor

Enchant creature
When this Aura enters, draw a card.
Enchanted creature has "{T}: Add one mana of any color."

Wind Strider

Flash (You may cast this spell any time you could cast an instant.)
Flying

Simic Cluestone

{T}: Add {G} or {U}.
{G}{U}, {T}, Sacrifice this artifact: Draw a card.

Rescue

Return target permanent you control to its owner's hand.

Khalni Heart Expedition

Landfall — Whenever a land you control enters, you may put a quest counter on this enchantment.
Remove three quest counters from this enchantment and sacrifice it: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

River Heralds' Boon

Put a +1/+1 counter on target creature and a +1/+1 counter on up to one target Merfolk.

Storm Sculptor

This creature can't be blocked.
When this creature enters, return a creature you control to its owner's hand.

Aggressive Urge

Target creature gets +1/+1 until end of turn.
Draw a card.

Forest

Rootwater Commando

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Simic Locket

{T}: Add {G} or {U}.
{G/U}{G/U}{G/U}{G/U}, {T}, Sacrifice this artifact: Draw two cards.

Broken Bond

Destroy target artifact or enchantment. You may put a land card from your hand onto the battlefield.

Scroll Thief

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

Titanic Growth

Target creature gets +4/+4 until end of turn.

Negate

Vodalian Arcanist

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.

Caller of Gales

{1}{U}, {T}: Target creature gains flying until end of turn.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Cosi's Trickster

Whenever an opponent shuffles their library, you may put a +1/+1 counter on this creature.

Coral Merfolk

Grip of the Roil

Surge {1}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Tap target creature. It doesn't untap during its controller's next untap step.
Draw a card.

Nyxborn Triton

Bestow {4}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Enchanted creature gets +2/+3.

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

Dive Down

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)