Fishliver Oil

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has islandwalk. (It can't be blocked as long as defending player controls an Island.)

Island

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.

Plains

Tolaria

{T}: Add {U}.
{T}: Target creature loses banding and all "bands with other" abilities until end of turn. Activate only during any upkeep step.

Enclave Elite

Multikicker {1}{U} (You may pay an additional {1}{U} any number of times as you cast this spell.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
This creature enters with a +1/+1 counter on it for each time it was kicked.

Benthic Behemoth

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

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.)

Rootwater Hunter

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

Portcullis

Whenever a creature enters, if there are two or more other creatures on the battlefield, exile that creature. Return that card to the battlefield under its owner's control when this artifact leaves the battlefield.

Spreading Seas

Enchant land
When this Aura enters, draw a card.
Enchanted land is an Island.

Oath of Teferi

When Oath of Teferi enters, exile another target permanent you control. Return it to the battlefield under its owner's control at the beginning of the next end step.
You may activate the loyalty abilities of planeswalkers you control twice each turn rather than only once.

Rebuke

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on this creature.
When this creature dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on this creature. (They can't be blocked as long as defending player controls an Island.)

Brilliant Plan

Twitch

You may tap or untap target artifact, creature, or land.
Draw a card.

Hornswoggle

Counter target creature spell. You create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Island Sanctuary

If you would draw a card during your draw step, instead you may skip that draw. If you do, until your next turn, you can't be attacked except by creatures with flying and/or islandwalk.

Wu Warship

This creature can't attack unless defending player controls an Island.

Harbor Serpent

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
This creature can't attack unless there are five or more Islands on the battlefield.

Seafarer's Quay

Blue legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Merfolk Raiders

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)

Winter Orb

As long as this artifact is untapped, players can't untap more than one land during their untap steps.

Crown of Awe

Enchant creature
Enchanted creature has protection from black and from red.
Sacrifice this Aura: Enchanted creature and other creatures that share a creature type with it gain protection from black and from red until end of turn.

Kukemssa Pirates

Whenever this creature attacks and isn't blocked, you may gain control of target artifact defending player controls. If you do, this creature assigns no combat damage this turn.

Ivory Tower

At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.

Talas Warrior

Kukemssa Serpent

This creature can't attack unless defending player controls an Island.
{U}, Sacrifice an Island: Target land an opponent controls becomes an Island until end of turn.
When you control no Islands, sacrifice this creature.

Backfire

Enchant creature
Whenever enchanted creature deals damage to you, this Aura deals that much damage to that creature's controller.

Jinxed Choker

At the beginning of your end step, target opponent gains control of this artifact and puts a charge counter on it.
At the beginning of your upkeep, this artifact deals damage to you equal to the number of charge counters on it.
{3}: Put a charge counter on this artifact or remove one from it.

Island Fish Jasconius

This creature doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {U}{U}{U}. If you do, untap this creature.
This creature can't attack unless defending player controls an Island.
When you control no Islands, sacrifice this creature.

Scourge of Fleets

When this creature enters, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Sandals of Abdallah

{2}, {T}: Target creature gains islandwalk until end of turn. When that creature dies this turn, destroy this artifact. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)

Teferi, Timebender

+2: Untap up to one target artifact or creature.
−3: You gain 2 life and draw two cards.
−9: Take an extra turn after this one.

Inkfathom Divers

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

Diamond Mare

As this creature enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Mutavault

{T}: Add {C}.
{1}: This land becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Spell Swindle

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Niambi, Faithful Healer

When Niambi enters, you may search your library and/or graveyard for a card named Teferi, Timebender, reveal it, and put it into your hand. If you search your library this way, shuffle.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Remote Isle

This land enters tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Kadena's Silencer

When Kadena's Silencer is turned face up, counter all abilities your opponents control.
Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Sailor of Means

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Living Wall

Defender (This creature can't attack.)
{1}: Regenerate Living Wall.

Colossal Whale

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature attacks, you may exile target creature defending player controls until this creature leaves the battlefield. (That creature returns under its owner's control.)

Devouring Deep

Prosperous Pirates

When this creature enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Mirrorpool

This land enters tapped.
{T}: Add {C}.
{2}{C}, {T}, Sacrifice this land: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}{C}, {T}, Sacrifice this land: Create a token that's a copy of target creature you control.

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Cathedral of Serra

White legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

War Barge

{3}: Target creature gains islandwalk until end of turn. When this artifact leaves the battlefield this turn, destroy that creature. A creature destroyed this way can't be regenerated. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)

Dovin, Architect of Law

+1: You gain 2 life and draw a card.
−1: Tap target creature. It doesn't untap during its controller's next untap step.
−9: Tap all permanents target opponent controls. That player skips their next untap step.

Single Combat

Each player chooses a creature or planeswalker they control, then sacrifices the rest. Players can't cast creature or planeswalker spells until the end of your next turn.

Warkite Marauder

Flying
Whenever this creature attacks, target creature defending player controls loses all abilities and has base power and toughness 0/1 until end of turn.

Gosta Dirk

First strike
Creatures with islandwalk can be blocked as though they didn't have islandwalk.

Merfolk Spy

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature deals combat damage to a player, that player reveals a card at random from their hand.

Phantom Ninja

Psionic Blast

Psionic Blast deals 4 damage to any target and 2 damage to you.

Island of Wak-Wak

{T}: Target creature with flying has base power 0 until end of turn.

Deeptread Merrow

{U}: This creature gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)

Skittering Invasion

Create five 0/1 colorless Eldrazi Spawn creature tokens. They have "Sacrifice this token: Add {C}."

Siren Stormtamer

Flying
{U}, Sacrifice this creature: Counter target spell or ability that targets you or a creature you control.

Sand Squid

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
You may choose not to untap Sand Squid during your untap step.
{T}: Tap target creature. That creature doesn't untap during its controller's untap step for as long as Sand Squid remains tapped.

Negate

Coral Barrier

Defender (This creature can't attack.)
When this creature enters, create a 1/1 blue Squid creature token with islandwalk. (It can't be blocked as long as defending player controls an Island.)

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.

Undertow

Creatures with islandwalk can be blocked as though they didn't have islandwalk.

Deadeye Quartermaster

When this creature enters, you may search your library for an Equipment or Vehicle card, reveal it, put it into your hand, then shuffle.

Merfolk Assassin

{T}: Destroy target creature with islandwalk.

God-Eternal Kefnet

Flying
You may reveal the first card you draw each turn as you draw it. Whenever you reveal an instant or sorcery card this way, copy that card and you may cast the copy. That copy costs {2} less to cast.
When God-Eternal Kefnet dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Tarnished Citadel

{T}: Add {C}.
{T}: Add one mana of any color. This land deals 3 damage to you.

Teroh's Faithful

When this creature enters, you gain 4 life.

Ayesha Tanaka

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)
{T}: Counter target activated ability from an artifact source unless that ability's controller pays {W}. (Mana abilities can't be targeted.)

Sygg, River Guide

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{1}{W}: Target Merfolk you control gains protection from the color of your choice until end of turn.

Rishadan Footpad

When this creature enters, each opponent sacrifices a permanent of their choice unless they pay {2}.