Drowned Rusalka

{U}, Sacrifice a creature: Discard a card, then draw a card.

Body of Knowledge

Body of Knowledge's power and toughness are each equal to the number of cards in your hand.
You have no maximum hand size.
Whenever Body of Knowledge is dealt damage, draw that many cards.

Quick Study

Compelling Argument

Target player mills five cards.
Cycling {U} ({U}, Discard this card: Draw a card.)

Arcane Signet

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

Choking Tethers

Tap up to four target creatures.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Choking Tethers, you may tap target creature.

Thought Scour

Target player mills two cards.
Draw a card.

Curator of Mysteries

Flying
Whenever you cycle or discard another card, scry 1.
Cycling {U} ({U}, Discard this card: Draw a card.)

Island

Floodwaters

Return up to two target creatures to their owners' hands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Fellwar Stone

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

Cloud of Faeries

Flying
When Cloud of Faeries enters, untap up to two lands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Sol Ring

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.)

High Tide

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

Abandoned Sarcophagus

You may cast spells that have a cycling ability from your graveyard.
If a card that has a cycling ability would be put into your graveyard from anywhere and it wasn't cycled, exile it instead.

Startling Development

Until end of turn, target creature becomes a blue Serpent with base power and toughness 4/4.
Cycling {1} ({1}, Discard this card: Draw a card.)

Spell Snip

Counter target spell unless its controller pays {1}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Tetsuko Umezawa, Fugitive

Creatures you control with power or toughness 1 or less can't be blocked.

Rebuild

Return all artifacts to their owners' hands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Krovikan Mist

Flying
Krovikan Mist's power and toughness are each equal to the number of Illusions on the battlefield.

Phantom Steed

Flash
When Phantom Steed enters, exile another target creature you control until Phantom Steed leaves the battlefield.
Whenever Phantom Steed attacks, create a tapped and attacking token that's a copy of the exiled card, except it's an Illusion in addition to its other types. Sacrifice that token at end of combat.

Hieroglyphic Illumination

Draw two cards.
Cycling {U} ({U}, Discard this card: Draw a card.)

Mnemonic Nexus

Each player shuffles their graveyard into their library.

Hampering Snare

Creatures your opponents control get -2/-0 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Vizier of Tumbling Sands

{T}: Untap another target permanent.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Vizier of Tumbling Sands, untap target permanent.

Enter the Enigma

Target creature can't be blocked this turn.
Draw a card.

Seafaring Werewolf

Seafaring Werewolf can't be blocked.
Whenever Seafaring Werewolf deals combat damage to a player, draw a card.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Suspicious Stowaway

Suspicious Stowaway can't be blocked.
Whenever Suspicious Stowaway deals combat damage to a player, draw a card, then discard a card.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Suspicious Stowaway // Seafaring Werewolf

Teferi's Ageless Insight

If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Fractured Sanity

Each opponent mills fourteen cards.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Fractured Sanity, each opponent mills four cards.

Dissipate

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Boon of the Wish-Giver

Draw four cards.
Cycling {1} ({1}, Discard this card: Draw a card.)

Brainstorm

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

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Peek

Look at target player's hand.
Draw a card.

Censor

Counter target spell unless its controller pays {1}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Neutralize

Counter target spell.
Cycling {2} ({2}, Discard this card: Draw a card.)

Alandra, Sky Dreamer

Whenever you draw your second card each turn, create a 2/2 blue Drake creature token with flying.
Whenever you draw your fifth card each turn, Alandra, Sky Dreamer and Drakes you control each get +X/+X until end of turn, where X is the number of cards in your hand.

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Talrand, Sky Summoner

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

Desert of the Mindful

Desert of the Mindful enters tapped.
{T}: Add {U}.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

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.

Keeneye Aven

Flying
Cycling {2} ({2}, Discard this card: Draw a card.)

Oneirophage

Flying
Whenever you draw a card, put a +1/+1 counter on Oneirophage.

Mage's Guile

Target creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
Cycling {U} ({U}, Discard this card: Draw a card.)

River Serpent

River Serpent can't attack unless there are five or more cards in your graveyard.
Cycling {U} ({U}, Discard this card: Draw a card.)

Unstable Obelisk

{T}: Add {C}.
{7}, {T}, Sacrifice Unstable Obelisk: Destroy target permanent.

Fluctuator

Cycling abilities you activate cost {2} less to activate.

Negate

Minn, Wily Illusionist

Whenever you draw your second card each turn, create a 1/1 blue Illusion creature token with "This creature gets +1/+0 for each other Illusion you control."
Whenever an Illusion you control dies, you may put a permanent card with mana value less than or equal to that creature's power from your hand onto the battlefield.

Disrupt

Counter target instant or sorcery spell unless its controller pays {1}.
Draw a card.

Meloku the Clouded Mirror

Flying
{1}, Return a land you control to its owner's hand: Create a 1/1 blue Illusion creature token with flying.

Illusory Ambusher

Flash (You may cast this spell any time you could cast an instant.)
Whenever Illusory Ambusher is dealt damage, draw that many cards.

Thought Vessel

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

Frostveil Ambush

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.
Cycling {1} ({1}, Discard this card: Draw a card.)