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.)

Counterspell

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Artificial Evolution

Change the text of target spell or permanent by replacing all instances of one creature type with another. The new creature type can't be Wall. (This effect lasts indefinitely.)

Arcane Adaptation

As this enchantment enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Rattlechains

Flash
Flying
When this creature enters, target Spirit gains hexproof until end of turn.
You may cast Spirit spells as though they had flash.

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.

Mishra's Factory

{T}: Add {C}.
{1}: This land becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Telling Time

Look at the top three cards of your library. Put one of those cards into your hand, one on top of your library, and one on the bottom of your library.

Diviner's Wand

Equipped creature has "Whenever you draw a card, this creature gets +1/+1 and gains flying until end of turn" and "{4}: Draw a card."
Whenever a Wizard creature enters, you may attach this Equipment to it.
Equip {3}

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Lord of Atlantis

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

Sudden Substitution

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Exchange control of target noncreature spell and target creature. Then the spell's controller may choose new targets for it.

Mirror Image

You may have this creature enter as a copy of a creature you control.

Merfolk Sovereign

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

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.

Griffin Canyon

{T}: Add {C}.
{T}: Untap target Griffin. If it's a creature, it gets +1/+1 until end of turn.

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Oathkeeper, Takeno's Daisho

Equipped creature gets +3/+1.
Whenever equipped creature dies, return that card to the battlefield under your control if it's a Samurai card.
When Oathkeeper is put into a graveyard from the battlefield, exile equipped creature.
Equip {2}

Rooftop Storm

You may pay {0} rather than pay the mana cost for Zombie creature spells you cast.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Mistform Warchief

Creature spells you cast that share a creature type with this creature cost {1} less to cast.
{T}: This creature becomes the creature type of your choice until end of turn.

Shapesharer

Changeling (This card is every creature type.)
{2}{U}: Target Shapeshifter becomes a copy of target creature until your next turn.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Skyline Cascade

This land enters tapped.
When this land enters, target creature an opponent controls doesn't untap during its controller's next untap step.
{T}: Add {U}.

Clever Impersonator

You may have this creature enter as a copy of any nonland permanent on the battlefield.

Mistform Ultimus

Mistform Ultimus is every creature type (even if this card isn't on the battlefield).

Obsidian Battle-Axe

Equipped creature gets +2/+1 and has haste.
Whenever a Warrior creature enters, you may attach this Equipment to it.
Equip {3}

Lord of the Unreal

Illusion creatures you control get +1/+1 and have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Universal Automaton

Changeling (This card is every creature type.)

Terrain Generator

{T}: Add {C}.
{2}, {T}: You may put a basic land card from your hand onto the battlefield tapped.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Stoneforge Masterwork

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}

Sol Ring

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Mimic Vat

Imprint — Whenever a nontoken creature dies, you may exile that card. If you do, return each other card exiled with this artifact to its owner's graveyard.
{3}, {T}: Create a token that's a copy of a card exiled with this artifact. It gains haste. Exile it at the beginning of the next end step.

Stunt Double

Flash
You may have this creature enter as a copy of any creature on the battlefield.

Long-Term Plans

Search your library for a card, then shuffle and put that card third from the top.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Clone

You may have this creature enter as a copy of any creature on the battlefield.

Knowledge Exploitation

Prowl {3}{U} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Rogue.)
Search target opponent's library for an instant or sorcery card. You may cast that card without paying its mana cost. Then that player shuffles.

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.

Paragon of Gathering Mists

Other blue creatures you control get +1/+1.
{U}, {T}: Another target blue creature you control gains flying until end of turn.

Island

Flusterstorm

Counter target instant or sorcery spell unless its controller pays {1}.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Telekinetic Sliver

All Slivers have "{T}: Tap target permanent."

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Turtleshell Changeling

Changeling (This card is every creature type.)
{1}{U}: Switch this creature's power and toughness until end of turn.

Dissipate

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Rewind

Counter target spell. Untap up to four lands.

Hall of Triumph

As Hall of Triumph enters, choose a color.
Creatures you control of the chosen color get +1/+1.

Wayfarer's Bauble

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

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.

Aetherize

Return all attacking creatures to their owner's hand.

Halimar Depths

This land enters tapped.
When this land enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Myr Galvanizer

Other Myr creatures you control get +1/+1.
{1}, {T}: Untap each other Myr you control.

Unesh, Criosphinx Sovereign

Flying
Sphinx spells you cast cost {2} less to cast.
Whenever Unesh or another Sphinx you control enters, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Mirage Mirror

{2}: This artifact becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Gadwick, the Wizened

When Gadwick enters, draw X cards.
Whenever you cast a blue spell, tap target nonland permanent an opponent controls.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Winged Sliver

Azami, Lady of Scrolls

Tap an untapped Wizard 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.)

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Call to the Kindred

Enchant creature
At the beginning of your upkeep, you may look at the top five cards of your library. If you do, you may put a creature card that shares a creature type with enchanted creature from among them onto the battlefield, then you put the rest of those cards on the bottom of your library in any order.

Cloak and Dagger

Equipped creature gets +2/+0 and has shroud. (It can't be the target of spells or abilities.)
Whenever a Rogue creature enters, you may attach this Equipment to it.
Equip {3}

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: This creature gains flying until end of turn.