Wormhole Serpent

{3}{U}: Target creature can't be blocked this turn.

Wavebreak Hippocamp

Whenever you cast your first spell during each opponent's turn, draw a card.

Access Denied

Counter target spell. Create X 1/1 colorless Thopter artifact creature tokens with flying, where X is that spell's mana value.

Omniscience

You may cast spells from your hand without paying their mana costs.

Gauntlet of Power

As Gauntlet of Power enters the battlefield, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Rewind

Counter target spell. Untap up to four lands.

Aetherspouts

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

Fatespinner

At the beginning of each opponent's upkeep, that player chooses draw step, main phase, or combat phase. The player skips each instance of the chosen step or phase this turn.

Naiad of Hidden Coves

As long as it's not your turn, spells you cast cost {1} less to cast.

Triskaidekaphile

You have no maximum hand size.
At the beginning of your upkeep, if you have exactly thirteen cards in your hand, you win the game.
{3}{U}: Draw a card.

Shrouded Serpent

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

Negate

Sol Ring

Gadwick, the Wizened

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

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Stonecoil Serpent

Reach, trample, protection from multicolored
Stonecoil Serpent enters the battlefield with X +1/+1 counters on it.

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.

Serpent of the Endless Sea

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

Aetherize

Return all attacking creatures to their owner's hand.

Counterspell

Stormsurge Kraken

Hexproof
Lieutenant — As long as you control your commander, Stormsurge Kraken gets +2/+2 and has "Whenever Stormsurge Kraken becomes blocked, you may draw two cards."

Aether Barrier

Whenever a player casts a creature spell, that player sacrifices a permanent unless they pay {1}.

Voracious Greatshark

Flash
When Voracious Greatshark enters the battlefield, counter target artifact or creature spell.

Cancel

Defabricate

Choose one —
• Counter target artifact or enchantment spell. If a spell is countered this way, exile it instead of putting it into its owner's graveyard.
• Counter target activated or triggered ability.

Inundate

Return all nonblue creatures to their owners' hands.

Archetype of Imagination

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

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.

Lullmage Mentor

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.

Guile

Guile can't be blocked except by three or more creatures.
If a spell or ability you control would counter a spell, instead exile that spell and you may play that card without paying its mana cost.
When Guile is put into a graveyard from anywhere, shuffle it into its owner's library.

Desertion

Counter target spell. If an artifact or creature spell is countered this way, put that card onto the battlefield under your control instead of into its owner's graveyard.

Monstrosity of the Lake

When Monstrosity of the Lake enters the battlefield, you may pay {5}. If you do, tap all creatures your opponents control, then put a stun counter on each of those creatures. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Dissolve

Counter target spell. Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Aether Adept

When Aether Adept enters the battlefield, return target creature to its owner's hand.

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.

Venser's Journal

You have no maximum hand size.
At the beginning of your upkeep, you gain 1 life for each card in your hand.

Unwind

Counter target noncreature spell. Untap up to three lands.

Kraken of the Straits

Creatures with power less than the number of Islands you control can't block Kraken of the Straits.

Shark Typhoon

Whenever you cast a noncreature spell, create an X/X blue Shark creature token with flying, where X is that spell's mana value.
Cycling {X}{1}{U} ({X}{1}{U}, Discard this card: Draw a card.)
When you cycle Shark Typhoon, create an X/X blue Shark creature token with flying.

Tamiyo, the Moon Sage

+1: Tap target permanent. It doesn't untap during its controller's next untap step.
−2: Draw a card for each tapped creature target player controls.
−8: You get an emblem with "You have no maximum hand size" and "Whenever a card is put into your graveyard from anywhere, you may return it to your hand."

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Charix, the Raging Isle

Spells your opponents cast that target Charix, the Raging Isle cost {2} more to cast.
{3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.

Arcanis the Omnipotent

{T}: Draw three cards.
{2}{U}{U}: Return Arcanis the Omnipotent to its owner's hand.

Draining Whelk

Flash
Flying
When Draining Whelk enters the battlefield, counter target spell. Put X +1/+1 counters on Draining Whelk, where X is that spell's mana value.

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.

Counterbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Patron Wizard

Tap an untapped Wizard you control: Counter target spell unless its controller pays {1}.

Frost Breath

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Bane's Contingency

Counter target spell. If that spell targets a commander you control, instead counter that spell, scry 2, then draw a card.

Fog Bank

Defender, flying
Prevent all combat damage that would be dealt to and dealt by Fog Bank.

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.

The Great Synthesis

(As this Saga enters and after your draw step, add a lore counter.)
I — Draw cards equal to the number of cards in your hand. You have no maximum hand size for as long as you control The Great Synthesis.
II — Return all non-Phyrexian creatures to their owners' hands.
III — You may cast any number of spells from your hand without paying their mana costs. Exile The Great Synthesis, then return it to the battlefield (front face up).

Jin-Gitaxias

Ward {2}
Whenever you cast a noncreature spell with mana value 3 or greater, draw a card.
{3}{U}: Exile Jin-Gitaxias, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if you have seven or more cards in hand.

Jin-Gitaxias // The Great Synthesis

Capsizing Wave

Return target creature to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Sword Coast Serpent

Sword Coast Serpent can't be blocked as long as you've cast a noncreature spell this turn.

Sword Coast Serpent // Capsizing Wave

Jace, Unraveler of Secrets

+1: Scry 1, then draw a card.
−2: Return target creature to its owner's hand.
−8: You get an emblem with "Whenever an opponent casts their first spell each turn, counter that spell."

Scourge of Fleets

When Scourge of Fleets enters the battlefield, 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.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Caged Sun

As Caged Sun enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

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.

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 the battlefield, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Island

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.)

Breaching Leviathan

When Breaching Leviathan enters the battlefield, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Jace's Sanctum

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Whelming Wave

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

Spellbook

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.