Justice

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

Burrenton Forge-Tender

Protection from red
Sacrifice Burrenton Forge-Tender: Prevent all damage a red source of your choice would deal this turn.

Red Ward

Enchant creature
Enchanted creature has protection from red. This effect doesn't remove Red Ward.

Tivadar of Thorn

First strike, protection from red
When Tivadar of Thorn enters, destroy target Goblin.

Sway of Illusion

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

Sphere of Law

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

Have

Circle of Protection: Red

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

Distorting Lens

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

Prismwake Merrow

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

Luminesce

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

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.

Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on Soulherder.
At the beginning of your end step, you may exile another target creature you control, then return that card to the battlefield under its owner's control.

Knockout Blow

This spell costs {2} less to cast if it targets a red creature.
Knockout Blow deals 4 damage to target attacking or blocking creature and you gain 2 life.

Barrenton Cragtreads

Barrenton Cragtreads can't be blocked by red creatures.

Teleportation Circle

At the beginning of your end step, exile up to one target artifact or creature you control, then return that card to the battlefield under its owner's control.

Lawbringer

{T}, Sacrifice Lawbringer: Exile target red creature.

Sisay's Ingenuity

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

Isochron Scepter

Imprint — When Isochron Scepter enters, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

Rasputin, the Oneiromancer

When Rasputin, the Oneiromancer 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.

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.

Wrath of Marit Lage

When Wrath of Marit Lage enters, tap all red creatures.
Red creatures don't untap during their controllers' untap steps.

Scuttlemutt

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

Red Scarab

Enchant creature
Enchanted creature can't be blocked by red creatures.
Enchanted creature gets +2/+2 as long as an opponent controls a red permanent.

Tidebinder Mage

When Tidebinder Mage enters, tap target red or green creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Tidebinder Mage.

Hydroblast

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

Surge of Righteousness

Destroy target black or red creature that's attacking or blocking. You gain 2 life.

Encase in Ice

Flash (You may cast this spell any time you could cast an instant.)
Enchant red or green creature
When Encase in Ice enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Prismatic Lace

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

Quickchange

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

Flash Flood

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

Pursued Whale

When Pursued Whale enters, each opponent creates a 1/1 red Pirate creature token with "This creature can't block" and "Creatures you control attack each combat if able."
Spells your opponents cast that target Pursued Whale cost {3} more to cast.

Shifting Sky

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

Vodalian Mystic

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

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Crimson Acolyte

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

Crown of Awe

Enchant creature
Enchanted creature has protection from black and from red.
Sacrifice Crown of Awe: Enchanted creature and other creatures that share a creature type with it gain protection from black and from red until end of turn.

Celestial Purge

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Blue Elemental Blast

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

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.)

Douse

Farrelite Priest

{1}: Add {W}. If this ability has been activated four or more times this turn, sacrifice Farrelite Priest at the beginning of the next end step.

Tidal Visionary

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

Blind Seer

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

Righteous Indignation

Whenever a creature blocks a black or red creature, the blocking creature gets +1/+1 until end of turn.

Honorable Scout

When Honorable Scout enters, you gain 2 life for each black and/or red creature target opponent controls.

Southern Paladin

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

Hunted Phantasm

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

Dream Coat

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