Runaway Steam-Kin

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

Duergar Mine-Captain

{1}{R/W}, {Q}: Attacking creatures get +1/+0 until end of turn. ({Q} is the untap symbol.)

Battle Cry Goblin

{1}{R}: Goblins you control get +1/+0 and gain haste until end of turn.
Pack tactics — Whenever this creature attacks, if you attacked with creatures with total power 6 or greater this combat, create a 1/1 red Goblin creature token that's tapped and attacking.

Legion Warboss

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
At the beginning of combat on your turn, create a 1/1 red Goblin creature token. That token gains haste until end of turn and attacks this combat if able.

Tome of the Guildpact

Whenever you cast a multicolored spell, draw a card.
{T}: Add one mana of any color.

Defiler of Instinct

First strike
As an additional cost to cast red permanent spells, you may pay 2 life. Those spells cost {R} less to cast if you paid life this way. This effect reduces only the amount of red mana you pay.
Whenever you cast a red permanent spell, this creature deals 1 damage to any target.

Goblin Surveyor

Trample
Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
Max speed — {3}, Exile this card from your graveyard: Draw a card.

Skirk Prospector

Impromptu Raid

{2}{R/G}: Reveal the top card of your library. If it isn't a creature card, put it into your graveyard. Otherwise, put that card onto the battlefield. That creature gains haste. Sacrifice it at the beginning of the next end step.

Kulrath Knight

Flying
Wither (This deals damage to creatures in the form of -1/-1 counters.)
Creatures your opponents control with counters on them can't attack or block.

Guttural Response

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Guild Artisan

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, you create two Treasure tokens." (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Lobber Crew

Defender
{T}: This creature deals 1 damage to each opponent.
Whenever you cast a multicolored spell, untap this creature.

Avishkar Raceway

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{T}: Add {C}.
Max speed — {3}, {T}, Discard a card: Draw a card.

Goblin Assault

At the beginning of your upkeep, create a 1/1 red Goblin creature token with haste.
Goblin creatures attack each combat if able.

Everlasting Torment

Players can't gain life.
Damage can't be prevented.
All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

Balefire Liege

Other red creatures you control get +1/+1.
Other white creatures you control get +1/+1.
Whenever you cast a red spell, this creature deals 3 damage to target player or planeswalker.
Whenever you cast a white spell, you gain 3 life.

Burnout Bashtronaut

Menace
Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{2}: This creature gets +1/+0 until end of turn.
Max speed — This creature has double strike.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Nobilis of War

Flying
Attacking creatures you control get +2/+0.

Bitter Reunion

When this enchantment enters, you may discard a card. If you do, draw two cards.
{1}, Sacrifice this enchantment: Creatures you control gain haste until end of turn.

Hearthfire Hobgoblin

Pyroconvergence

Whenever you cast a multicolored spell, this enchantment deals 2 damage to any target.

Boros Strike-Captain

Battalion — Whenever this creature and at least two other creatures attack, exile the top card of your library. During any turn you attacked with three or more creatures, you may play that card.

Angrath, Captain of Chaos

Creatures you control have menace.
−2: Amass Zombies 2. (Put two +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Sunset Strikemaster

{T}: Add {R}.
{2}{R}, {T}, Sacrifice this creature: It deals 6 damage to target creature with flying.

Runes of the Deus

Enchant creature
As long as enchanted creature is red, it gets +1/+1 and has double strike. (It deals both first-strike and regular combat damage.)
As long as enchanted creature is green, it gets +1/+1 and has trample.

Blade Historian

Attacking creatures you control have double strike.

Hazoret's Monument

Red creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, you may discard a card. If you do, draw a card.

Goblin Rabblemaster

Other Goblin creatures you control attack each combat if able.
At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste.
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Ashenmoor Liege

Other black creatures you control get +1/+1.
Other red creatures you control get +1/+1.
Whenever this creature becomes the target of a spell or ability an opponent controls, that player loses 4 life.

Double Cleave

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

Howlsquad Heavy

Start your engines!
Other Goblins you control have haste.
At the beginning of combat on your turn, create a 1/1 red Goblin creature token. That token attacks this combat if able.
Max speed — {T}: Add {R} for each Goblin you control.

Clout of the Dominus

Enchant creature
As long as enchanted creature is blue, it gets +1/+1 and has shroud. (It can't be the target of spells or abilities.)
As long as enchanted creature is red, it gets +1/+1 and has haste.

Mountain

Amonkhet Raceway

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
{T}: Add {C}.
Max speed — {T}: Target creature gains haste until end of turn.

Noggle Bandit

This creature can't be blocked except by creatures with defender.

Glittering Stockpile

{T}: Add {R}. Put a stash counter on this artifact.
{T}, Sacrifice this artifact: Add X mana of any one color, where X is the number of stash counters on this artifact.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Rise of the Hobgoblins

When this enchantment enters, you may pay {X}. If you do, create X 1/1 red and white Goblin Soldier creature tokens.
{R/W}: Red creatures and white creatures you control gain first strike until end of turn.

Psychotic Fury

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

Siege-Gang Lieutenant

Lieutenant — At the beginning of combat on your turn, if you control your commander, create two 1/1 red Goblin creature tokens. Those tokens gain haste until end of turn.
{2}, Sacrifice a Goblin: This creature deals 1 damage to any target.

Kickoff Celebrations

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
When this enchantment enters, you may discard a card. If you do, draw two cards.
Max speed — Sacrifice this enchantment: Creatures and Vehicles you control gain haste until end of turn.

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.)

Ecstatic Electromancer

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever this creature enters or attacks, you may discard a card. If you do, draw a card.

Dominus of Fealty

Flying
At the beginning of your upkeep, you may gain control of target permanent until end of turn. If you do, untap it and it gains haste until end of turn.

Shattering Blow

Boros Reckoner

Whenever this creature is dealt damage, it deals that much damage to any target.
{R/W}: This creature gains first strike until end of turn.

Mindwrack Liege

Other blue creatures you control get +1/+1.
Other red creatures you control get +1/+1.
{U/R}{U/R}{U/R}{U/R}: You may put a blue or red creature card from your hand onto the battlefield.

Pit Fight

Target creature you control fights another target creature. (Each deals damage equal to its power to the other.)

Spiteful Visions

At the beginning of each player's draw step, that player draws an additional card.
Whenever a player draws a card, this enchantment deals 1 damage to that player.

Endrider Catalyzer

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
Max speed — {T}: Add {R}{R}.

Make Your Mark

Target creature gets +1/+0 until end of turn. When that creature dies this turn, create a 3/2 red and white Spirit creature token.

Nahiri, Storm of Stone

During your turn, creatures you control have first strike and equip abilities you activate cost {1} less to activate.
−X: Nahiri deals X damage to target tapped creature.

Howling Mine

At the beginning of each player's draw step, if this artifact is untapped, that player draws an additional card.

Searslicer Goblin

Raid — At the beginning of your end step, if you attacked this turn, create a 1/1 red Goblin creature token.

Squee, Dubious Monarch

Haste
Whenever Squee attacks, create a 1/1 red Goblin creature token that's tapped and attacking.
You may cast this card from your graveyard by paying {3}{R} and exiling four other cards from your graveyard rather than paying its mana cost.

Krenko, Tin Street Kingpin

Whenever Krenko attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power.

Fiery Bombardment

Chroma — {2}, Sacrifice a creature: This enchantment deals damage to any target equal to the number of red mana symbols in the sacrificed creature's mana cost.

Mana Cannons

Whenever you cast a multicolored spell, this enchantment deals X damage to any target, where X is the number of colors that spell is.

Endrider Spikespitter

Reach
Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
Max speed — At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.

Cursed Mirror

{T}: Add {R}.
As this artifact enters, you may have it become a copy of any creature on the battlefield until end of turn, except it has haste.

Spitemare

Whenever this creature is dealt damage, it deals that much damage to any target.

Waves of Aggression

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Brazen Cannonade

Whenever an attacking creature you control dies, this enchantment deals 2 damage to each opponent.
Raid — At the beginning of each of your postcombat main phases, if you attacked this turn, exile the top card of your library. Until end of combat on your next turn, you may play that card.

Outpace Oblivion

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
When this enchantment enters, it deals 5 damage to up to one target creature or planeswalker.
{2}, Sacrifice this enchantment: It deals 2 damage to each player who doesn't have max speed.

Anax, Hardened in the Forge

Anax's power is equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)
Whenever Anax or another nontoken creature you control dies, create a 1/1 red Satyr creature token with "This token can't block." If the creature had power 4 or greater, create two of those tokens instead.

Giantbaiting

Create a 4/4 red and green Giant Warrior creature token with haste. Exile it at the beginning of the next end step.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it.)