Morphic Pool

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Spark Double

You may have this creature enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

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.

Shipbreaker Kraken

{6}{U}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, tap up to four target creatures. Those creatures don't untap during their controllers' untap steps for as long as you control this creature.

Fellwar Stone

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

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Junk Winder

Affinity for tokens (This spell costs {1} less to cast for each token you control.)
Whenever a token you control enters, tap target nonland permanent an opponent controls. It doesn't untap during its controller's next untap step.

Serpent of Yawning Depths

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

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Swamp

Temple of Deceit

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {B}.

Slinn Voda, the Rising Deep

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

Giant's Amulet

When this Equipment enters, you may pay {3}{U}. If you do, create a 4/4 blue Giant Wizard creature token, then attach this Equipment to it.
Equipped creature gets +0/+1 and has "This creature has hexproof as long as it's untapped."(It can't be the target of spells or abilities your opponents control.)
Equip {2}

Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
This artifact enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on this artifact.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Bender's Waterskin

Untap this artifact during each other player's untap step.
{T}: Add one mana of any color.

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.

Worn Powerstone

This artifact enters tapped.
{T}: Add {C}{C}.

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

Conspiracy

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

Whelming Wave

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Mortuary Mire

This land enters tapped.
When this land enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Dark Ritual

Krothuss, Lord of the Deep

Flying
Whenever Krothuss attacks, create a tapped and attacking token that's a copy of another target attacking creature. If that creature is a Kraken, Leviathan, Octopus, or Serpent, create two of those tokens instead.

Runo Stromkirk

Flying
When Runo enters, put up to one target creature card from your graveyard on top of your library.
At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If a creature card with mana value 6 or greater is revealed this way, transform Runo.

Runo Stromkirk // Krothuss, Lord of the Deep

Obsessive Stitcher

{T}: Draw a card, then discard a card.
{2}{U}{B}, {T}, Sacrifice this creature: Return target creature card from your graveyard to the battlefield.

Wonder

Flying
As long as this card is in your graveyard and you control an Island, creatures you control have flying.

Otherworldly Gaze

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Sea-Dasher Octopus

Mutate {1}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Temple of the False God

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

Gilded Lotus

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Island

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Dimir Aqueduct

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Aetherize

Return all attacking creatures to their owner's hand.

Deep-Sea Kraken

This creature 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 this card is suspended, remove a time counter from it.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Lavaspur Boots

Equipped creature gets +1/+0 and has haste and ward {1}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
Equip {1}

Arcane Signet

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

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Aetherspouts

For each attacking creature, its owner puts it on their choice of the top or bottom of their library.

Mind Stone

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

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Thryx, the Sudden Storm

Flash (You may cast this spell any time you could cast an instant.)
Flying
Spells you cast with mana value 5 or greater cost {1} less to cast and can't be countered.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Reliquary Tower

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

Rogue's Passage

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

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.

Sol Ring

Sky Diamond

This artifact enters tapped.
{T}: Add {U}.

Kiora Bests the Sea God

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create an 8/8 blue Kraken creature token with hexproof.
II — Tap all nonland permanents target opponent controls. They don't untap during their controller's next untap step.
III — Gain control of target permanent an opponent controls. Untap it.

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.

Gyruda, Doom of Depths

Companion — Your starting deck contains only cards with even mana values. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Gyruda enters, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Thought Vessel

Darkwater Catacombs

Exotic Orchard

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

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.

Nadir Kraken

Whenever you draw a card, you may pay {1}. If you do, put a +1/+1 counter on this creature and create a 1/1 blue Tentacle creature token.

Charcoal Diamond

This artifact enters tapped.
{T}: Add {B}.

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.

Port of Karfell

This land enters tapped.
{T}: Add {U}.
{3}{U}{B}{B}, {T}, Sacrifice this land: Mill four cards, then return a creature card from your graveyard to the battlefield tapped. (To mill a card, put the top card of your library into your graveyard.)

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Command Tower

Myriad Landscape

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

Summon: Leviathan

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Return each creature that isn't a Kraken, Leviathan, Merfolk, Octopus, or Serpent to its owner's hand.
II, III — Until end of turn, whenever a Kraken, Leviathan, Merfolk, Octopus, or Serpent attacks, draw a card.
Ward {2}

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Thran Dynamo

Shipwreck Marsh

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Chameleon, Master of Disguise

You may have Chameleon enter as a copy of a creature you control, except his name is Chameleon, Master of Disguise.
Mayhem {2}{U} (You may cast this card from your graveyard for {2}{U} if you discarded it this turn. Timing rules still apply.)

Lochmere Serpent

Flash
{U}, Sacrifice an Island: This creature can't be blocked this turn.
{B}, Sacrifice a Swamp: You gain 1 life and draw a card.
{U}{B}: Exile five target cards from an opponent's graveyard. Return this card from your graveyard to your hand. Activate only as a sorcery.

Dimir Signet

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Evolving Wilds

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

Ominous Seas

Whenever you draw a card, put a foreshadow counter on this enchantment.
Remove eight foreshadow counters from this enchantment: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Terramorphic Expanse

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

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.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.