Mana Leak

Counter target spell unless its controller pays {3}.

Merfolk Coralsmith

{1}: Merfolk Coralsmith gets +1/-1 until end of turn.
When Merfolk Coralsmith dies, scry 2.

Kiora, Sovereign of the Deep

Vigilance, ward {3}
Whenever you cast a Kraken, Leviathan, Octopus, or Serpent spell from your hand, look at the top X cards of your library, where X is that spell's mana value. You may cast a spell with mana value less than X from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

Compulsive Research

Target player draws three cards. Then that player discards two cards unless they discard a land card.

Vineglimmer Snarl

As Vineglimmer Snarl enters, you may reveal a Forest or Island card from your hand. If you don't, Vineglimmer Snarl enters tapped.
{T}: Add {G} or {U}.

Elvish Rejuvenator

When Elvish Rejuvenator enters, look at the top five cards of your library. You may put a land card from among them onto the battlefield tapped. Put the rest on the bottom of your library in a random order.

Garruk's Uprising

When Garruk's Uprising enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample.
Whenever a creature you control with power 4 or greater enters, draw a card.

Harvest Season

Search your library for up to X basic land cards, where X is the number of tapped creatures you control, put those cards onto the battlefield tapped, then shuffle.

Quandrix Campus

Quandrix Campus enters tapped.
{T}: Add {G} or {U}.
{4}, {T}: Scry 1.

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Vodalian Hexcatcher

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

Sleight of Hand

Look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Scourge of Fleets

When Scourge of Fleets 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.

Jaheira's Respite

Search your library for up to X basic land cards, where X is the number of creatures attacking you, put those cards onto the battlefield tapped, then shuffle.
Prevent all combat damage that would be dealt this turn.

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.)

Many Partings

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Whelming Wave

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

Serpent of Yawning Depths

Krakens, Leviathans, Octopuses, and Serpents you control can't be blocked except by Krakens, Leviathans, Octopuses, and Serpents.

Dawntreader Elk

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

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Monstrous Vortex

Whenever you cast a creature spell with power 5 or greater, discover X, where X is that spell's mana value. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Out of the Way

This spell costs {2} less to cast if it targets a green permanent.
Return target nonland permanent an opponent controls to its owner's hand.
Draw a card.

Forest

Triton Wavebreaker

Bestow {1}{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.)
As long as Triton Wavebreaker is a creature, it has prowess. (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Enchanted creature gets +1/+1 and has prowess.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Naturalize

Tangled Islet

({T}: Add {G} or {U}.)
Tangled Islet enters tapped.

Bounty of the Luxa

At the beginning of your first main phase, remove all flood counters from Bounty of the Luxa. If no counters were removed this way, put a flood counter on Bounty of the Luxa and draw a card. Otherwise, add {C}{G}{U}.

Spawning Kraken

Whenever a Kraken, Leviathan, Octopus, or Serpent you control deals combat damage to a player, create a 9/9 blue Kraken creature token.

Quasiduplicate

Create a token that's a copy of target creature you control.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Command Tower

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Up the Beanstalk

When Up the Beanstalk enters and whenever you cast a spell with mana value 5 or greater, draw a card.

Voda Sea Scavenger

Domain — When Voda Sea Scavenger enters, look at the top X cards of your library, where X is the number of basic land types among lands you control. You may put one of those cards on top of your library. Put the rest on the bottom of your library in a random order.

Brokers Hideout

When Brokers Hideout enters, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Thriving Isle

Thriving Isle enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Negate

Inkwell Leviathan

Trample
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Shroud (This creature can't be the target of spells or abilities.)

Tyvar's Stand

Target creature you control gets +X/+X and gains hexproof and indestructible until end of turn. (A creature with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Lórien Revealed

Draw three cards.
Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Skyclave Relic

Kicker {3}
Indestructible
When Skyclave Relic enters, if it was kicked, create two tapped tokens that are copies of Skyclave Relic.
{T}: Add one mana of any color.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Thran Dynamo

Island

Quandrix Cultivator

When Quandrix Cultivator enters, you may search your library for a basic Forest or Island card, put it onto the battlefield, then shuffle.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Ilysian Caryatid

{T}: Add one mana of any color. If you control a creature with power 4 or greater, add two mana of any one color instead.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Sol Ring

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Wilt

Destroy target artifact or enchantment.
Cycling {2} ({2}, Discard this card: Draw a card.)

Simic Sky Swallower

Flying, trample
Shroud (This creature can't be the target of spells or abilities.)

Somberwald Sage

{T}: Add three mana of any one color. Spend this mana only to cast creature spells.

Slinn Voda, the Rising Deep

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
When Slinn Voda, the Rising Deep enters, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Entish Restoration

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. If you control a creature with power 4 or greater, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Joint Exploration

Kicker {G} (You may pay an additional {G} as you cast this spell.)
Scry 2, then draw a card. If this spell was kicked, you may put a land card from your hand onto the battlefield.

Cultivate

Troyan, Gutsy Explorer

{T}: Add {G}{U}. Spend this mana only to cast spells with mana value 5 or greater or spells with {X} in their mana costs.
{U}, {T}: Draw a card, then discard a card.

Deep-Sea Kraken

Deep-Sea Kraken can't be blocked.
Suspend 9—{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with nine time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever an opponent casts a spell, if Deep-Sea Kraken is suspended, remove a time counter from it.

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Lantern of the Lost

When Lantern of the Lost enters, exile target card from a graveyard.
{1}, {T}, Exile Lantern of the Lost: Exile all cards from all graveyards, then draw a card.

Reservoir Kraken

Trample, ward {2}
At the beginning of each combat, if Reservoir Kraken is untapped, any opponent may tap an untapped creature they control. If they do, tap Reservoir Kraken and create a 1/1 blue Fish creature token with "This creature can't be blocked."

Reef Worm

When Reef Worm dies, create a 3/3 blue Fish creature token with "When this creature dies, create a 6/6 blue Whale creature token with 'When this creature dies, create a 9/9 blue Kraken creature token.'"

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Stormkeld Prowler

Whenever you cast a spell with mana value 5 or greater, put two +1/+1 counters on Stormkeld Prowler.

Geistwave

Return target nonland permanent to its owner's hand. If you controlled that permanent, draw a card.