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.

Forest

Ornithopter of Paradise

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sultai Skullkeeper

When Sultai Skullkeeper enters, mill two cards.

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Aesi, Tyrant of Gyre Strait

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, you may draw a card.

Brinelin, the Moon Kraken

When Brinelin, the Moon Kraken enters and whenever you cast a spell with mana value 6 or greater, you may return target nonland permanent to its owner's hand.
Partner (You can have two commanders if both have partner.)

Command Tower

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

Vizier of Many Faces

You may have Vizier of Many Faces enter as a copy of any creature on the battlefield, except if Vizier of Many Faces was embalmed, the token has no mana cost, it's white, and it's a Zombie in addition to its other types.
Embalm {3}{U}{U}

Sidisi, Brood Tyrant

Whenever Sidisi, Brood Tyrant enters or attacks, mill three cards.
Whenever one or more creature cards are put into your graveyard from your library, create a 2/2 black Zombie creature token.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Mire Triton

Deathtouch
When Mire Triton enters, mill two cards and you gain 2 life. (To mill a card, put the top card of your library into your graveyard.)

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Defense of the Heart

At the beginning of your upkeep, if an opponent controls three or more creatures, sacrifice Defense of the Heart, search your library for up to two creature cards, put those cards onto the battlefield, then shuffle.

Deranged Assistant

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Wonder

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

Burning-Rune Demon

Flying
When Burning-Rune Demon enters, you may search your library for exactly two cards not named Burning-Rune Demon that have different names. If you do, reveal those cards. An opponent chooses one of them. Put the chosen card into your hand and the other into your graveyard, then shuffle.

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.

Glowspore Shaman

When Glowspore Shaman enters, mill three cards. You may put a land card from your graveyard on top of your library. (To mill a card, put the top card of your library into your graveyard.)

Solemn Simulacrum

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

Stunt Double

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

Lorthos, the Tidemaker

Whenever Lorthos, the Tidemaker attacks, you may pay {8}. If you do, tap up to eight target permanents. Those permanents don't untap during their controllers' next untap steps.

Lightning Greaves

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

Brawn

Trample
As long as Brawn is in your graveyard and you control a Forest, creatures you control have trample.

Esior, Wardwing Familiar

Flying
Spells your opponents cast that target one or more commanders you control cost {3} more to cast.
Partner (You can have two commanders if both have partner.)

Sakashima the Impostor

You may have Sakashima the Impostor enter as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step."

Dreamscape Artist

{2}{U}, {T}, Discard a card, Sacrifice a land: Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Denizen of the Deep

When Denizen of the Deep enters, return each other creature you control to its owner's hand.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Evil Twin

You may have Evil Twin enter as a copy of any creature on the battlefield, except it has "{U}{B}, {T}: Destroy target creature with the same name as this creature."

Clone

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

Verdant Catacombs

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

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.

Undergrowth Stadium

Undergrowth Stadium enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Muldrotha, the Gravetide

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

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.

Serpent of Yawning Depths

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

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Tidal Barracuda

Any player may cast spells as though they had flash.
Your opponents can't cast spells during your turn.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Island

Seal of Primordium

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Tormod, the Desecrator

Whenever one or more cards leave your graveyard, create a tapped 2/2 black Zombie creature token.
Partner (You can have two commanders if both have partner.)

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.

Gigantoplasm

You may have Gigantoplasm enter as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X."

Thran Dynamo

Path of Ancestry

Path of Ancestry 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.)

Witchbane Orb

When Witchbane Orb enters, destroy all Curses attached to you.
You have hexproof. (You can't be the target of spells or abilities your opponents control, including Aura spells.)

Spellskite

{U/P}: Change a target of target spell or ability to Spellskite. ({U/P} can be paid with either {U} or 2 life.)

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.

Dance of the Dead

Enchant creature card in a graveyard
When Dance of the Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Dance of the Dead." Put enchanted creature card onto the battlefield tapped under your control and attach Dance of the Dead to it. When Dance of the Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets +1/+1 and doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player may pay {1}{B}. If the player does, untap that creature.

Clever Impersonator

You may have Clever Impersonator enter as a copy of any nonland permanent on the battlefield.

Giant Octopus

World Shaper

Whenever World Shaper attacks, you may mill three cards.
When World Shaper dies, return all land cards from your graveyard to the battlefield tapped.

Paradise Druid

This creature has hexproof as long as it's untapped. (It can't be the target of spells or abilities your opponents control.)
{T}: Add one mana of any color.

Skull Prophet

{T}: Add {B} or {G}.
{T}: Mill two cards.

Mirror Mockery

Enchant creature
Whenever enchanted creature attacks, you may create a token that's a copy of that creature. Exile that token at end of combat.

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Glen Elendra Archmage

Flying
{U}, Sacrifice Glen Elendra Archmage: Counter target noncreature spell.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Kederekt Leviathan

When Kederekt Leviathan enters, return all other nonland permanents to their owners' hands.
Unearth {6}{U} ({6}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Millikin

Dawntreader Elk

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

Satyr Wayfinder

When Satyr Wayfinder enters, reveal the top four cards of your library. You may put a land card from among them into your hand. Put the rest into your graveyard.

Swamp

Spark Double

You may have Spark Double 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.

Vile Entomber

Deathtouch
When Vile Entomber enters, search your library for a card, put that card into your graveyard, then shuffle.

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.

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 Shipbreaker Kraken becomes monstrous, tap up to four target creatures. Those creatures don't untap during their controllers' untap steps for as long as you control Shipbreaker Kraken.

Opulent Palace

Opulent Palace enters tapped.
{T}: Add {B}, {G}, or {U}.

Arcane Signet

Sunken Hollow

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

Lochmere Serpent

Flash
{U}, Sacrifice an Island: Lochmere Serpent 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 Lochmere Serpent from your graveyard to your hand. Activate only as a sorcery.

Phantasmal Image

You may have Phantasmal Image enter as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."