Blind Seer

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

Pentarch Paladin

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
As this creature enters, choose a color.
{W}{W}, {T}: Destroy target permanent of the chosen color.

Rasputin, the Oneiromancer

When Rasputin enters, put a dream counter on it for each opponent you have. Each opponent creates a 1/1 red Goblin creature token.
{T}, Remove one or more dream counters from Rasputin: Add that much {C}.
{T}, Remove a dream counter from Rasputin: Create a 2/2 white Knight creature token with protection from red.

Honorable Passage

The next time a source of your choice would deal damage to any target this turn, prevent that damage. If damage from a red source is prevented this way, Honorable Passage deals that much damage to the source's controller.

Aether Gust

Choose target spell or permanent that's red or green. Its owner puts it on their choice of the top or bottom of their library.

Prismatic Lace

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

Flash Flood

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

Well-Laid Plans

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

Rune of Protection: Red

{W}: The next time a red source of your choice would deal damage to you this turn, prevent that damage.
Cycling {2} ({2}, Discard this card: Draw a card.)

Hydroblast

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

Absolute Law

Shifting Sky

As this enchantment enters, choose a color.
All nonland permanents are the chosen color.

Sphere of Law

If a red source would deal damage to you, prevent 2 of that damage.

Scuttlemutt

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

Samite Ministration

Prevent all damage that would be dealt to you this turn by a source of your choice. Whenever damage from a black or red source is prevented this way this turn, you gain that much life.

Prismwake Merrow

Flash
When this creature enters, target permanent becomes the color or colors of your choice until end of turn.

Sway of Illusion

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

Douse

Distorting Lens

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

Kor Firewalker

Protection from red
Whenever a player casts a red spell, you may gain 1 life.

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.

Blue Elemental Blast

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

Circle of Protection: Red

{1}: The next time a red source of your choice would deal damage to you this turn, prevent that damage.

Story Circle

As this enchantment enters, choose a color.
{W}: The next time a source of your choice of the chosen color would deal damage to you this turn, prevent that damage.

Crimson Acolyte

Protection from red
{W}: Target creature gains protection from red until end of turn.

Mangara's Equity

As this enchantment enters, choose black or red.
At the beginning of your upkeep, sacrifice this enchantment unless you pay {1}{W}.
Whenever a creature of the chosen color deals damage to you or a white creature you control, this enchantment deals that much damage to that creature.

Hunted Phantasm

This creature can't be blocked.
When this creature enters, target opponent creates five 1/1 red Goblin creature tokens.

Luminesce

Prevent all damage that black sources and red sources would deal this 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.

Greater Realm of Preservation

{1}{W}: The next time a black or red source of your choice would deal damage to you this turn, prevent that damage.

Justice

At the beginning of your upkeep, sacrifice this enchantment unless you pay {W}{W}.
Whenever a red creature or spell deals damage, this enchantment deals that much damage to that creature's or spell's controller.

Quickchange

Target creature becomes the color or colors of your choice until end of turn.
Draw a card.

Surge of Salvation

You and permanents you control gain hexproof until end of turn. Prevent all damage that black and/or red sources would deal to creatures you control this turn.

Tidal Visionary

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

Prismatic Strands

Prevent all damage that sources of the color of your choice would deal this turn.
Flashback—Tap an untapped white creature you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Pilgrim of Justice

Protection from red
{W}, Sacrifice this creature: The next time a red source of your choice would deal damage this turn, prevent that damage.

Sisay's Ingenuity

Enchant creature
When this Aura enters, draw a card.
Enchanted creature has "{2}{U}: Target creature becomes the color of your choice until end of turn."

Celestial Purge

Wrath of Marit Lage

When this enchantment enters, tap all red creatures.
Red creatures don't untap during their controllers' untap steps.

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.

Southern Paladin

{W}{W}, {T}: Destroy target red permanent.

Burrenton Forge-Tender

Protection from red
Sacrifice this creature: Prevent all damage a red source of your choice would deal this turn.

Teferi's Moat

As this enchantment enters, choose a color.
Creatures of the chosen color without flying can't attack you.

Sanctifier en-Vec

Protection from black and from red
When this creature enters, exile all cards that are black or red from all graveyards.
If a black or red permanent, spell, or card not on the battlefield would be put into a graveyard, exile it instead.

Lightwielder Paladin

First strike (This creature deals combat damage before creatures without first strike.)
Whenever this creature deals combat damage to a player, you may exile target black or red permanent that player controls.