Dreamwinder

This creature can't attack unless defending player controls an Island.
{U}, Sacrifice an Island: Target land becomes an Island until end of turn.

Desynchronize

Target nonland permanent's owner puts it on their choice of the top or bottom of their library. Scry 2.

Gearseeker Serpent

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{5}{U}: This creature can't be blocked this turn.

Spire Serpent

Defender
Metalcraft - As long as you control three or more artifacts, this creature gets +2/+2 and can attack as though it didn't have defender.

Horn of Ramos

{T}: Add {G}.
Sacrifice this artifact: Add {G}.

Woodland Mystic

Beneath the Sands

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Cycling {2} ({2}, Discard this card: Draw a card.)

Deep-Sea Terror

This creature can't attack unless there are seven or more cards in your graveyard.

Artisan's Sorrow

Destroy target artifact or enchantment. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Marjhan

This creature doesn't untap during your untap step.
{U}{U}, Sacrifice a creature: Untap this creature. Activate only during your upkeep.
This creature can't attack unless defending player controls an Island.
{U}{U}: This creature gets -1/-0 until end of turn and deals 1 damage to target attacking creature without flying.
When you control no Islands, sacrifice this creature.

Segovian Leviathan

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

Elemental Resonance

Enchant permanent
At the beginning of your first main phase, add mana equal to enchanted permanent's mana cost. (Mana cost includes color. If a mana symbol has multiple colors, choose one.)

Blue Mana Battery

{2}, {T}: Put a charge counter on this artifact.
{T}, Remove any number of charge counters from this artifact: Add {U}, then add an additional {U} for each charge counter removed this way.

Green Mana Battery

{2}, {T}: Put a charge counter on this artifact.
{T}, Remove any number of charge counters from this artifact: Add {G}, then add an additional {G} for each charge counter removed this way.

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Deep Reconnaissance

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
Flashback {4}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Thoughtleech

Whenever an Island an opponent controls becomes tapped, you may gain 1 life.

Kiora's Dambreaker

When this creature enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Frilled Sea Serpent

{5}{U}{U}: This creature can't be blocked this turn.

Tel-Jilad Justice

Destroy target artifact. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Island

Forest

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.

Anchor to the Aether

Put target creature on top of its owner's library. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Horizon Seeker

Boast — {1}{G}: Search your library for a basic land card, reveal it, put it into your hand, then shuffle. (Activate only if this creature attacked this turn and only once each turn.)

Sliptide Serpent

{3}{U}: Return this creature to its owner's hand.

Giant Octopus

Godhunter Octopus

This creature can't attack unless defending player controls an enchantment or an enchanted permanent.

Biblioplex Kraken

When this creature enters, scry 3. (Look at the top three cards of your library, then put any number of them on the bottom and the rest on top in any order.)
Whenever this creature attacks, you may return another creature you control to its owner's hand. If you do, this creature can't be blocked this turn.

Sea Serpent

This creature can't attack unless defending player controls an Island.
When you control no Islands, sacrifice this creature.

Arboria

Creatures can't attack a player unless that player cast a spell or put a nontoken permanent onto the battlefield during their last turn.

Stymied Hopes

Counter target spell unless its controller pays {1}. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sea Monster

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

Kenessos, Priest of Thassa

If you would scry a number of cards, scry that many cards plus one instead.
{3}{G/U}: Look at the top card of your library. If it's a Kraken, Leviathan, Octopus, or Serpent creature card, you may put it onto the battlefield. If you don't put the card onto the battlefield, you may put it on the bottom of your library.

Eye of Ramos

{T}: Add {U}.
Sacrifice this artifact: Add {U}.

Tolarian Terror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Shoal Kraken

Constellation — Whenever an enchantment you control enters, you may draw a card. If you do, discard a card.

Clear the Land

Each player reveals the top five cards of their library, puts all land cards revealed this way onto the battlefield tapped, and exiles the rest.

Isleback Spawn

Shroud (This creature can't be the target of spells or abilities.)
This creature gets +4/+8 as long as a library has twenty or fewer cards in it.

Candles of Leng

{4}, {T}: Reveal the top card of your library. If it has the same name as a card in your graveyard, put it into your graveyard. Otherwise, draw a card.

Sol Grail

As this artifact enters, choose a color.
{T}: Add one mana of the chosen color.

Serpent of the Endless Sea

Serpent of the Endless Sea's power and toughness are each equal to the number of Islands you control.
This creature can't attack unless defending player controls an Island.

Dirgur Nemesis

Defender
Megamorph {6}{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.)

Ferocious Charge

Target creature gets +4/+4 until end of turn. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Sealock Monster

This creature can't attack unless defending player controls an Island.
{5}{U}{U}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, target land becomes an Island in addition to its other types.

Accumulated Knowledge

Draw a card, then draw cards equal to the number of cards named Accumulated Knowledge in all graveyards.

Cryptic Serpent

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.

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.

Biolume Serpent

Sacrifice two Islands: This creature can't be blocked this turn.

Biolume Egg

Defender
When this creature enters, scry 2.
When you sacrifice this creature, return it to the battlefield transformed under its owner's control at the beginning of the next end step.

Biolume Egg // Biolume Serpent

Shoal Serpent

Defender
Landfall — Whenever a land you control enters, this creature loses defender until end of turn.

Shrouded Serpent

Whenever this creature attacks, defending player may pay {4}. If that player doesn't, this creature can't be blocked this turn.

Descendant of Soramaro

{1}{U}: Look at the top X cards of your library, where X is the number of cards in your hand, then put them back in any order.

Chain to Memory

Target creature gets -4/-0 until end of turn. Scry 2.

Carnivorous Canopy

Destroy target artifact, enchantment, or creature with flying. If that permanent's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Slipstream Serpent

This creature can't attack unless defending player controls an Island.
When you control no Islands, sacrifice this creature.
Morph {5}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Impede Momentum

Tap target creature and put three stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Mana Prism

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

Steelclad Serpent

This creature can't attack unless you control another artifact.

Thirsting Roots

Choose one —
• Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Serum Powder

{T}: Add {C}.
Any time you could mulligan and this card is in your hand, you may exile all the cards from your hand, then draw that many cards. (You can do this in addition to taking mulligans.)

So Shiny

Enchant creature
When this Aura enters, if you control a token, tap enchanted creature, then scry 2.
Enchanted creature doesn't untap during its controller's untap step.