Vodalian Mystic

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

Tidal Visionary

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

Command Tower

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

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Dromar, the Banisher

Flying
Whenever Dromar, the Banisher deals combat damage to a player, you may pay {2}{U}. If you do, choose a color, then return all creatures of that color to their owners' hands.

Warped Devotion

Whenever a permanent is returned to a player's hand, that player discards a card.

Flooded Woodlands

Green creatures can't attack unless their controller sacrifices a land of their choice for each green creature they control that's attacking. (This cost is paid as attackers are declared.)

Dimir Signet

Exotic Orchard

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

Order of the Sacred Torch

{T}, Pay 1 life: Counter target black spell.

Arcane Signet

Shifting Sky

As Shifting Sky enters, 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.

Plains

Island

Dream Coat

Enchant creature
{0}: Enchanted creature becomes the color or colors of your choice. Activate only once each turn.

Change the Equation

Choose one —
• Counter target spell with mana value 2 or less.
• Counter target red or green spell with mana value 6 or less.

Blind Seer

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

Azorius Signet

Robe of Stars

Equipped creature gets +0/+3.
Astral Projection — {1}{W}: Equipped creature phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
Equip {1}

Perish

Destroy all green creatures. They can't be regenerated.

Ersatz Gnomes

{T}: Target spell becomes colorless.
{T}: Target permanent becomes colorless until end of turn.

Llawan, Cephalid Empress

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

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.)

Douse

Hibernation

Return all green permanents to their owners' hands.

Sway of Illusion

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

Swamp

Scuttlemutt

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

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.)

Trait Doctoring

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.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Deathgrip

Eight-and-a-Half-Tails

{1}{W}: Target permanent you control gains protection from white until end of turn.
{1}: Target spell or permanent becomes white until end of turn.

Orzhov Signet

Sol Ring

Govern the Guildless

Gain control of target monocolored creature.
Forecast — {1}{U}, Reveal Govern the Guildless from your hand: Target creature becomes the color or colors of your choice until end of turn. (Activate only during your upkeep and only once each turn.)