Counterspell

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.

Spontaneous Mutation

Flash
Enchant creature
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.

Remove Soul

Fencer Clique

Flying
{U}: Put Fencer Clique on top of its owner's library.

Dream Thief

Flying
When Dream Thief enters, draw a card if you've cast another blue spell this turn.

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

High Tide

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

Tome Raider

Flying
When Tome Raider enters, draw a card.

Spellstutter Sprite

Flash
Flying
When Spellstutter Sprite enters, counter target spell with mana value X or less, where X is the number of Faeries you control.

Abjure

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

Shadow Rift

Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)
Draw a card.

Briarberry Cohort

Flying
Briarberry Cohort gets +1/+1 as long as you control another blue creature.

Faerie Invaders

Flash (You may cast this spell any time you could cast an instant.)
Flying

Distant Melody

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

Winter Eladrin

Gust of Wind — When Winter Eladrin enters, return up to one other target creature to its owner's hand.

Spy Network

Look at target player's hand, the top card of that player's library, and any face-down creatures they control. Look at the top four cards of your library, then put them back in any order.

Faerie Seer

Flying
When Faerie Seer enters, 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.)

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

Serum Visions

Faerie Trickery

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

Cloud of Faeries

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

Mental Note

Thought Scour

Target player mills two cards.
Draw a card.

Unwind

Counter target noncreature spell. Untap up to three lands.

Perilous Research

Draw two cards, then sacrifice a permanent.

Surveilling Sprite

Flying
When Surveilling Sprite dies, you may draw a card.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Think Twice

Draw a card.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Brainstorm

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

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.