Insight

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

Blind Seer

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

Mana Maze

Players can't cast spells that share a color with the spell most recently cast this turn.

Cryptoplasm

At the beginning of your upkeep, you may have Cryptoplasm become a copy of another target creature, except it has this ability.

Master of Waves

Protection from red
Elemental creatures you control get +1/+1.
When Master of Waves enters, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Swirl the Mists

As Swirl the Mists enters, choose a color word.
All instances of color words in the text of spells and permanents are changed to the chosen color word.

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.)

Homarid Shaman

Well-Laid Plans

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

Cackling Counterpart

Create a token that's a copy of target creature you control.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Blue Elemental Blast

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

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.)

Scuttlemutt

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

Sower of Temptation

Flying
When Sower of Temptation enters, gain control of target creature for as long as Sower of Temptation remains on the battlefield.

Stunt Double

Flash
You may have Stunt Double enter as a copy of any creature on the battlefield.

Back to Basics

Nonbasic lands don't untap during their controllers' untap steps.

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Hydroblast

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

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 Willbreaker.

Reliquary Tower

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

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.")

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.)

Vodalian Mystic

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

Dismiss into Dream

Each creature your opponents control is an Illusion in addition to its other types and has "When this creature becomes the target of a spell or ability, sacrifice it."

Mirage Mirror

{2}: Mirage Mirror becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Snow-Covered Island

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.)

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Tidal Control

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Pay 2 life or {2}: Counter target red or green spell. Any player may activate this ability.

Jaded Response

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

Flash Flood

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

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Tidal Visionary

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

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Counterspell

Clever Impersonator

You may have Clever Impersonator enter as a copy of any nonland permanent on the battlefield.

Desertion

Counter target spell. If an artifact or creature spell is countered this way, put that card onto the battlefield under your control instead of into its owner's graveyard.

Spectral Shift

Choose one —
• Change the text of target spell or permanent by replacing all instances of one basic land type with another. (This effect lasts indefinitely.)
• Change the text of target spell or permanent by replacing all instances of one color word with another. (This effect lasts indefinitely.)
Entwine {2} (Choose both if you pay the entwine cost.)

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.

Gigantoplasm

You may have Gigantoplasm enter as a copy of any creature on the battlefield, except it has "{X}: This creature has base power and toughness X/X."

Sway of Illusion

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

Clone

You may have Clone enter as a copy of any creature on the battlefield.

Blatant Thievery

For each opponent, gain control of target permanent that player controls.

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.)