Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.

Removings

Impact Resonance

Impact Resonance deals X damage divided as you choose among any number of target creatures, where X is the greatest amount of damage dealt by a source to a permanent or player this turn.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Exotic Orchard

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

Accelerate

Target creature gains haste until end of turn.
Draw a card.

Sheltering Light

Target creature gains indestructible until end of turn. Scry 1. (Damage and effects that say "destroy" don't destroy the creature.)

Expedite

Have

Iroas, God of Victory

Indestructible
As long as your devotion to red and white is less than seven, Iroas isn't a creature.
Creatures you control have menace.
Prevent all damage that would be dealt to attacking creatures you control.

Vanguard of Brimaz

Vigilance
Heroic — Whenever you cast a spell that targets Vanguard of Brimaz, create a 1/1 white Cat Soldier creature token with vigilance.

Niveous Wisps

Target creature becomes white until end of turn. Tap that creature.
Draw a card.

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, Hedron Grinder, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Fists of Flame

Draw a card. Until end of turn, target creature gains trample and gets +1/+0 for each card you've drawn this turn. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

Bathe in Light

Radiance — Choose a color. Target creature and each other creature that shares a color with it gain protection from the chosen color until end of turn.

Mirrorwing Dragon

Flying
Whenever a player casts an instant or sorcery spell that targets only Mirrorwing Dragon, that player copies that spell for each other creature they control that the spell could target. Each copy targets a different one of those creatures.

Emerge Unscathed

Target creature you control gains protection from the color of your choice until end of turn.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Titan's Strength

Target creature gets +3/+1 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Bandage

Prevent the next 1 damage that would be dealt to any target this turn.
Draw a card.

Swift Justice

Until end of turn, target creature gets +1/+0 and gains first strike and lifelink.

Fabled Hero

Double strike
Heroic — Whenever you cast a spell that targets Fabled Hero, put a +1/+1 counter on Fabled Hero.

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.

Plains

Mountain

Reliquary Tower

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

Otherworldly Journey

Exile target creature. At the beginning of the next end step, return that card to the battlefield under its owner's control with a +1/+1 counter on it.

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Duergar Hedge-Mage

When Duergar Hedge-Mage enters, if you control two or more Mountains, you may destroy target artifact.
When Duergar Hedge-Mage enters, if you control two or more Plains, you may destroy target enchantment.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Getting

Walking Atlas

{T}: You may put a land card from your hand onto the battlefield.

Adamant Will

Target creature gets +2/+2 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Akroan Crusader

Heroic — Whenever you cast a spell that targets Akroan Crusader, create a 1/1 red Soldier creature token with haste. (It can attack and {T} as soon as it comes under your control.)

Gods Willing

Target creature you control gains protection from the color of your choice until end of turn. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything of that color.)
Scry 1.

Burning Prophet

Whenever you cast a noncreature spell, Burning Prophet gets +1/+0 until end of turn, then scry 1.

Feather, the Redeemed

Flying
Whenever you cast an instant or sorcery spell that targets a creature you control, exile that card instead of putting it into your graveyard as it resolves. If you do, return it to your hand at the beginning of the next end step.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Assault Strobe

Target creature gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Guided Strike

Target creature gets +1/+0 and gains first strike until end of turn.
Draw a card.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Gift of Immortality

Enchant creature
When enchanted creature dies, return that card to the battlefield under its owner's control. Return Gift of Immortality to the battlefield attached to that creature at the beginning of the next end step.

Brute Force

Target creature gets +3/+3 until end of turn.

Sunforger

Equipped creature gets +4/+0.
{R}{W}, Unattach Sunforger: Search your library for a red or white instant card with mana value 4 or less and cast that card without paying its mana cost. Then shuffle.
Equip {3}

Akroan Conscriptor

Heroic — Whenever you cast a spell that targets Akroan Conscriptor, gain control of another target creature until end of turn. Untap that creature. It gains haste until end of turn.

Soul's Fire

Target creature you control deals damage equal to its power to any target.

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.

Psychotic Fury

Target multicolored creature gains double strike until end of turn.
Draw a card.

Seize the Day

Untap target creature. After this main phase, there is an additional combat phase followed by an additional main phase.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Crimson Wisps

Target creature becomes red and gains haste until end of turn. (It can attack and {T} this turn.)
Draw a card.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Command Tower

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

Clifftop Retreat

Clifftop Retreat enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Lost Vale

(Transforms from Dowsing Dagger.)
{T}: Add three mana of any one color.

Dowsing Dagger

When Dowsing Dagger enters, target opponent creates two 0/2 green Plant creature tokens with defender.
Equipped creature gets +2/+1.
Whenever equipped creature deals combat damage to a player, you may transform Dowsing Dagger.
Equip {2}

Dowsing Dagger // Lost Vale

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Twinflame

Strive — This spell costs {2}{R} more to cast for each target beyond the first.
Choose any number of target creatures you control. For each of them, create a token that's a copy of that creature, except it has haste. Exile those tokens at the beginning of the next end step.

Phalanx Leader

Heroic — Whenever you cast a spell that targets Phalanx Leader, put a +1/+1 counter on each creature you control.

Spellbook

Ajani's Presence

Strive — This spell costs {2}{W} more to cast for each target beyond the first.
Any number of target creatures each get +1/+1 and gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Justiciar's Portal

Exile target creature you control, then return that card to the battlefield under its owner's control. It gains first strike until end of turn.

Balduvian Rage

Target attacking creature gets +X/+0 until end of turn.
Draw a card at the beginning of the next turn's upkeep.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Slaughter the Strong

Each player chooses any number of creatures they control with total power 4 or less, then sacrifices all other creatures they control.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Precursor Golem

When Precursor Golem enters, create two 3/3 colorless Golem artifact creature tokens.
Whenever a player casts an instant or sorcery spell that targets only a single Golem, that player copies that spell for each other Golem that spell could target. Each copy targets a different one of those Golems.

Anax and Cymede

First strike, vigilance
Heroic — Whenever you cast a spell that targets Anax and Cymede, creatures you control get +1/+1 and gain trample until end of turn.

Mana Flare

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Kor Cartographer

When Kor Cartographer enters, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Defiant Strike

Target creature gets +1/+0 until end of turn.
Draw a card.

Shelter

Target creature you control gains protection from the color of your choice until end of turn.
Draw a card.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Mana Geyser

Add {R} for each tapped land your opponents control.

Rally the Righteous

Radiance — Untap target creature and each other creature that shares a color with it. Those creatures get +2/+0 until end of turn.

Myth Realized

Whenever you cast a noncreature spell, put a lore counter on Myth Realized.
{2}{W}: Put a lore counter on Myth Realized.
{W}: Until end of turn, Myth Realized becomes a Monk Avatar creature in addition to its other types and gains "This creature's power and toughness are each equal to the number of lore counters on it."

Fell the Mighty

Destroy all creatures with power greater than target creature's power.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.