Martyr of Frost

{2}, Reveal X blue cards from your hand, Sacrifice Martyr of Frost: Counter target spell unless its controller pays {X}.

Castle Vantress

Castle Vantress enters the battlefield tapped unless you control an Island.
{T}: Add {U}.
{2}{U}{U}, {T}: Scry 2.

Cursecatcher

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Sphinx's Herald

{2}{U}, {T}, Sacrifice a white creature, a blue creature, and a black creature: Search your library for a card named Sphinx Sovereign, put it onto the battlefield, then shuffle.

Prismatic Lens

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

Sol Ring

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Cathartic Adept

Timebender

Morph {U}
When Timebender is turned face up, choose one —
• Remove two time counters from target permanent or suspended card.
• Put two time counters on target permanent with a time counter on it or suspended card.

Sage of Epityr

When Sage of Epityr enters the battlefield, look at the top four cards of your library, then put them back in any order.

Sea Scryer

Abjure

As an additional cost to cast this spell, sacrifice a blue permanent.
Counter target spell.

Turn Aside

Counter target spell that targets a permanent you control.

Thought Vessel

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

Fugitive Wizard

Drifter il-Dal

Shadow (This creature can block or be blocked by only creatures with shadow.)
At the beginning of your upkeep, sacrifice Drifter il-Dal unless you pay {U}.

Mistcaller

Sacrifice Mistcaller: Until end of turn, if a nontoken creature would enter the battlefield and it wasn't cast, exile it instead.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Sage of Fables

Each other Wizard creature you control enters the battlefield with an additional +1/+1 counter on it.
{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Unctus, Grand Metatect

Other blue creatures you control have "Whenever this creature becomes tapped, draw a card, then discard a card."
Other artifact creatures you control get +1/+1.
{U/P}: Until end of turn, target creature you control becomes a blue artifact in addition to its other colors and types. Activate only as a sorcery. ({U/P} can be paid with either {U} or 2 life.)

Reliquary Tower

Benevolent Geist

Flying
Noncreature spells you control can't be countered.
If Benevolent Geist would be put into a graveyard from anywhere, exile it instead.

Malevolent Hermit

{U}, Sacrifice Malevolent Hermit: Counter target noncreature spell unless its controller pays {3}.
Disturb {2}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Malevolent Hermit // Benevolent Geist

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.

Sage of Mysteries

Constellation — Whenever an enchantment enters the battlefield under your control, target player mills two cards.

Thassa's Oracle

When Thassa's Oracle enters the battlefield, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Vedalken Certarch

Metalcraft — {T}: Tap target artifact, creature, or land. Activate only if you control three or more artifacts.

Information Dealer

{T}: Look at the top X cards of your library, where X is the number of Wizards on the battlefield, then put them back in any order.

Sidisi's Faithful

Exploit (When this creature enters the battlefield, you may sacrifice a creature.)
When Sidisi's Faithful exploits a creature, return target creature to its owner's hand.

Imagecrafter

{T}: Choose a creature type other than Wall. Target creature becomes that type until end of turn.

Drowner Initiate

Whenever a player casts a blue spell, you may pay {1}. If you do, target player mills two cards.

Windrider Wizard

Flying
Whenever you cast an instant, sorcery, or Wizard spell, you may draw a card. If you do, discard a card.

March of Swirling Mist

As an additional cost to cast this spell, you may exile any number of blue cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Up to X target creatures phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

Island

Frost Augur

{S}, {T}: Look at the top card of your library. If it's a snow card, you may reveal it and put it into your hand. ({S} can be paid with one mana from a snow source.)

Dramatic Reversal

Untap all nonland permanents you control.

Cosi's Trickster

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.
When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Realmwright

As Realmwright enters the battlefield, choose a basic land type.
Lands you control are the chosen type in addition to their other types.

Ipnu Rivulet

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{1}{U}, {T}, Sacrifice a Desert: Target player mills four cards.

Deranged Assistant

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

Symmetry Sage

Flying
Magecraft — Whenever you cast or copy an instant or sorcery spell, target creature you control has base power 2 until end of turn.

Dispel

Command Tower

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

Wingcrafter

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Wingcrafter is paired with another creature, both creatures have flying.

Caller of Gales

{1}{U}, {T}: Target creature gains flying until end of turn.

Rootwater Mystic

{1}{U}: Look at the top card of target player's library.

Tidal Visionary

{T}: Target creature becomes the color of your choice until end of turn.

Graaz, Unstoppable Juggernaut

Juggernauts you control attack each combat if able.
Juggernauts you control can't be blocked by Walls.
Other creatures you control have base power and toughness 5/3 and are Juggernauts in addition to their other creature types.

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Benthic Biomancer

{1}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Benthic Biomancer, draw a card, then discard a card.

Tideshaper Mystic

{T}: Target land becomes the basic land type of your choice until end of turn. Activate only during your turn.

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Naban, Dean of Iteration

If a Wizard entering the battlefield under your control causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Sky Diamond

Sky Diamond enters the battlefield tapped.
{T}: Add {U}.

Hapless Researcher

Sacrifice Hapless Researcher: Draw a card, then discard a card.

Faerie Seer

Flying
When Faerie Seer enters the battlefield, scry 2.

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Azami, Lady of Scrolls

Tap an untapped Wizard you control: Draw a card.

Overwhelmed Apprentice

When Overwhelmed Apprentice enters the battlefield, each opponent mills two cards. Then you scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Defiler of Dreams

Flying
As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay.
Whenever you cast a blue permanent spell, draw a card.

Decanter of Endless Water

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

Dakra Mystic

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Riptide Director

{2}{U}{U}, {T}: Draw a card for each Wizard you control.

Enclave Cryptologist

Level up {1}{U} ({1}{U}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
0/1
{T}: Draw a card, then discard a card.
LEVEL 3+
0/1
{T}: Draw a card.

Voidmage Prodigy

{U}{U}, Sacrifice a Wizard: Counter target spell.
Morph {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.)

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Delver of Secrets // Insectile Aberration

Kefnet's Monument

Blue creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Arcane Signet

Grixis Illusionist

{T}: Target land you control becomes the basic land type of your choice until end of turn.

Flow of Knowledge

Draw a card for each Island you control, then discard two cards.

Skywatcher Adept

Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying

Tide Shaper

Kicker {1} (You may pay an additional {1} as you cast this spell.)
When Tide Shaper enters the battlefield, if it was kicked, target land becomes an Island for as long as Tide Shaper remains on the battlefield.
Tide Shaper gets +1/+1 as long as an opponent controls an Island.

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.