Sway of Illusion

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

Glamerdye

Change the text of target spell or permanent by replacing all instances of one color word with another.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Douse

Merchant Scroll

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

Painter's Servant

As this creature enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Sapphire Medallion

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

Hydroblast

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

Sol Ring

Distorting Lens

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

Wash Out

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

Scuttlemutt

{T}: Add one mana of any color.
{T}: Target creature becomes the color or colors of your choice until end of turn.

King Crab

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

Willbreaker

Whenever a creature an opponent controls becomes the target of a spell or ability you control, gain control of that creature for as long as you control this creature.

Grindstone

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

Llawan, Cephalid Empress

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

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Blind Seer

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

Tidal Visionary

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

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.

High Tide

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

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.)