Hibernation

Return all green permanents to their owners' hands.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Brainstorm

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

Sol Ring

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Barrin's Unmaking

Return target permanent to its owner's hand if that permanent shares a color with the most common color among all permanents or a color tied for most common.

Alter Reality

Change the text of target spell or permanent by replacing all instances of one color word with another. (This effect lasts indefinitely.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Baleful Stare

Target opponent reveals their hand. You draw a card for each Mountain and red card in it.

Jaded Response

Counter target spell if it shares a color with a creature you control.

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Chameleon Spirit

As Chameleon Spirit enters the battlefield, choose a color.
Chameleon Spirit's power and toughness are each equal to the number of permanents of the chosen color your opponents control.

Sleight of Mind

Change the text of target spell or permanent by replacing all instances of one color word with another. (For example, you may change "target black spell" to "target blue spell." This effect lasts indefinitely.)

Insight

Whenever an opponent casts a green spell, you draw a card.

Well-Laid Plans

Prevent all damage that would be dealt to a creature by another creature if they share a color.

Cowardice

Whenever a creature becomes the target of a spell or ability, return that creature to its owner's hand. (It won't be affected by the spell or ability.)

Gainsay

Ether Well

Put target creature on top of its owner's library. If that creature is red, you may put it on the bottom of its owner's library instead.

Wash Out

Return all permanents of the color of your choice to their owners' hands.

Llawan, Cephalid Empress

When Llawan, Cephalid Empress enters the battlefield, return all blue creatures your opponents control to their owners' hands.
Your opponents can't cast blue creature spells.

Withering Gaze

Target opponent reveals their hand. You draw a card for each Forest and green card in it.

Fylamarid

Flying
Fylamarid can't be blocked by blue creatures.
{U}: Target creature becomes blue until end of turn.

Douse

Sea Kings' Blessing

One or more target creatures become blue until end of turn.

Island

Blind Seer

{1}{U}: Target spell or permanent becomes the color of your choice until end of turn.

Arcanis the Omnipotent

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

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Riptide

Grindstone

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

Flash Flood

Choose one —
• Destroy target red permanent.
• Return target Mountain to its owner's hand.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

King Crab

{1}{U}, {T}: Put target green creature on top of its owner's library.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Sway of Illusion

Any number of target creatures become the color of your choice until end of turn.
Draw a card.

Prismatic Lace

Target permanent becomes the color or colors of your choice. (This effect lasts indefinitely.)

Tidal Visionary

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

Spellbook

Whim of Volrath

Buyback {2} (You may pay an additional {2} as you cast this spell. If you do, put this card into your hand as it resolves.)
Change the text of target permanent by replacing all instances of one color word with another or one basic land type with another until end of turn. (For example, you may change "nonred creature" to "nongreen creature" or "plainswalk" to "swampwalk.")

Crystal Spray

Change the text of target spell or permanent by replacing all instances of one color word with another or one basic land type with another until end of turn.
Draw a card.

Merchant Scroll

Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.

Counterspell

Vodalian Mystic

{T}: Target instant or sorcery spell becomes the color of your choice.

Shifting Sky

As Shifting Sky enters the battlefield, choose a color.
All nonland permanents are the chosen color.

Distorting Lens

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

Metathran Transport

Flying
Metathran Transport can't be blocked by blue creatures.
{U}: Target creature becomes blue until end of turn.