Have

Koth, Fire of Resistance

+2: Search your library for a basic Mountain card, reveal it, put it into your hand, then shuffle.
−3: Koth deals damage to target creature equal to the number of Mountains you control.
−7: You get an emblem with "Whenever a Mountain you control enters, this emblem deals 4 damage to any target."

Impulsive Pilferer

When this creature dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Encore {3}{R} ({3}{R}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Boltbender

Disguise {1}{R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, you may choose new targets for any number of other spells and/or abilities.

Reckless Lackey

First strike, haste
{2}{R}, Sacrifice this creature: Draw a card and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Forgotten Cave

This land enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Goblin Goliath

When this creature enters, create a number of 1/1 red Goblin creature tokens equal to the number of opponents you have.
{3}{R}, {T}: If a source you control would deal damage to an opponent this turn, it deals double that damage to that player instead.

Flare of Duplication

You may sacrifice a nontoken red creature rather than pay this spell's mana cost.
Copy target instant or sorcery spell. You may choose new targets for the copy.

Urabrask's Forge

At the beginning of combat on your turn, put an oil counter on this artifact, then create an X/1 red Phyrexian Horror creature token with trample and haste, where X is the number of oil counters on this artifact. Sacrifice that token at the beginning of the next end step.

Loyal Apprentice

Haste
Lieutenant — At the beginning of combat on your turn, if you control your commander, create a 1/1 colorless Thopter artifact creature token with flying. That token gains haste until end of turn.

Empty the Warrens

Create two 1/1 red Goblin creature tokens.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Quarrel's End

As an additional cost to cast this spell, discard a card.
Draw two cards and create a 1/1 white Human Soldier creature token.

Mountain

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Gleeful Demolition

Destroy target artifact. If you controlled that artifact, create three 1/1 red Phyrexian Goblin creature tokens.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

Magus of the Wheel

{1}{R}, {T}, Sacrifice this creature: Each player discards their hand, then draws seven cards.

Seething Song

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Mana Geyser

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

Ral's Reinforcements

Create two 1/1 blue and red Elemental creature tokens.

Blood Moon

Wayfarer's Bauble

{2}, {T}, Sacrifice this artifact: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Inspired Tinkering

Exile the top three cards of your library. Until the end of your next turn, you may play those cards.
Create three Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Rally at the Hornburg

Create two 1/1 white Human Soldier creature tokens. Humans you control gain haste until end of turn.

Goblin Rally

Create four 1/1 red Goblin creature tokens.

Coal Stoker

When this creature enters, if you cast it from your hand, add {R}{R}{R}.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

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.

Goblin Instigator

When this creature enters, create a 1/1 red Goblin creature token.

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.

Feldon of the Third Path

{2}{R}, {T}: Create a token that's a copy of target creature card in your graveyard, except it's an artifact in addition to its other types. It gains haste. Sacrifice it at the beginning of the next end step.

Searslicer Goblin

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

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}.

Mogg War Marshal

Echo {1}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters or dies, create a 1/1 red Goblin creature token.

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.

Goblin Surprise

Choose one —
• Creatures you control get +2/+0 until end of turn.
• Create two 1/1 red Goblin creature tokens.

Goblin Charbelcher

{3}, {T}: Reveal cards from the top of your library until you reveal a land card. This artifact deals damage equal to the number of nonland cards revealed this way to any target. If the revealed land card was a Mountain, this artifact deals double that damage instead. Put the revealed cards on the bottom of your library in any order.

Getting

Skullclamp

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

General Kreat, the Boltbringer

Whenever one or more Goblins you control attack, create a 1/1 red Goblin creature token that's tapped and attacking.
Whenever another creature you control enters, General Kreat deals 1 damage to each opponent.

Grinning Ignus

{R}, Return this creature to its owner's hand: Add {C}{C}{R}. Activate only as a sorcery.

Pyroblast

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

Goblin Warchief

Goblin spells you cast cost {1} less to cast.
Goblins you control have haste.

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Rousing Refrain

Add {R} for each card in target opponent's hand. Until end of turn, you don't lose this mana as steps and phases end. Exile Rousing Refrain with three time counters on it.
Suspend 3—{1}{R} (Rather than cast this card from your hand, you may pay {1}{R} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Mimic Vat

Imprint — Whenever a nontoken creature dies, you may exile that card. If you do, return each other card exiled with this artifact to its owner's graveyard.
{3}, {T}: Create a token that's a copy of a card exiled with this artifact. It gains haste. Exile it at the beginning of the next end step.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Sol Ring

Norin, Swift Survivalist

Norin can't block.
Whenever a creature you control becomes blocked, you may exile it. You may play that card from exile this turn.

Skirk Prospector

Battle Hymn

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Izzet Chemister

Haste
{R}, {T}: Exile target instant or sorcery card from your graveyard.
{1}{R}, {T}, Sacrifice this creature: Cast any number of cards exiled with this creature without paying their mana costs.

Ib Halfheart, Goblin Tactician

Whenever another Goblin you control becomes blocked, sacrifice it. If you do, it deals 4 damage to each creature blocking it.
Sacrifice two Mountains: Create two 1/1 red Goblin creature tokens.

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.

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.

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.

Nyx Lotus

Nyx Lotus enters tapped.
{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.)

Overmaster

The next instant or sorcery spell you cast this turn can't be countered.
Draw a card.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Tempt with Vengeance

Tempting offer — Create X 1/1 red Elemental creature tokens with haste. Each opponent may create X 1/1 red Elemental creature tokens with haste. For each opponent who does, create X 1/1 red Elemental creature tokens with haste.

Orthion, Hero of Lavabrink

{1}{R}, {T}: Create a token that's a copy of another target creature you control. It gains haste. Sacrifice it at the beginning of the next end step. Activate only as a sorcery.
{6}{R}{R}{R}, {T}: Create five tokens that are copies of another target creature you control. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.

Dualcaster Mage

Flash
When this creature enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Kher Keep

{T}: Add {C}.
{1}{R}, {T}: Create a 0/1 red Kobold creature token named Kobolds of Kher Keep.

Norin the Wary

When a player casts a spell or a creature attacks, exile Norin. Return it to the battlefield under its owner's control at the beginning of the next end step.

Krenko's Command

Siege-Gang Commander

When this creature enters, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: This creature deals 2 damage to any target.

Count on Luck

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.