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}.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Storm-Kiln Artist

Storm-Kiln Artist gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

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.

Sol Ring

Ancestral Anger

Target creature gains trample and gets +X/+0 until end of turn, where X is 1 plus the number of cards named Ancestral Anger in your graveyard.
Draw a card.

Skirk Prospector

Battle Hymn

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Manakin

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.

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 of your library.)

Accelerate

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

Krenko, Tin Street Kingpin

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

Renegade Tactics

Target creature can't block this turn.
Draw a card.

Kick in the Door

Put a +1/+1 counter on target creature. That creature gains haste until end of turn and can't be blocked by Walls this turn. Venture into the dungeon. (Enter the first room or advance to the next room.)

Ancestors' Aid

Target creature gets +2/+0 and gains first strike until end of turn.
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Forgotten Cave

Forgotten Cave enters the battlefield tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Flick a Coin

Flick a Coin deals 1 damage to any target. You create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Draw a card.

Witch's Mark

You may discard a card. If you do, draw two cards.
Create a Wicked Role token attached to up to one target creature you control. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)

Arcane Signet

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

Stun

Goblinslide

Whenever you cast a noncreature spell, you may pay {1}. If you do, create a 1/1 red Goblin creature token with haste.

Guttersnipe

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

Kari Zev's Expertise

Gain control of target creature or Vehicle until end of turn. Untap it. It gains haste until end of turn.
You may cast a spell with mana value 2 or less from your hand without paying its mana cost.

Molten Duplication

Create a token that's a copy of target artifact or creature you control, except it's an artifact in addition to its other types. It gains haste until end of turn. Sacrifice it at the beginning of the next end step.

Goblin Matron

When Goblin Matron enters the battlefield, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Brute Force

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

Crimson Wisps

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

Iron Myr

Monstrous Rage

Target creature gets +2/+0 until end of turn. Create a Monster Role token attached to it. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 and has trample.)

Mountain

Siege-Gang Commander

When Siege-Gang Commander enters the battlefield, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.

Reliquary Tower

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

Kher Keep

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

Beetleback Chief

When Beetleback Chief enters the battlefield, create two 1/1 red Goblin creature tokens.

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Reckless Charge

Target creature gets +3/+0 and gains haste until end of turn.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Felonious Rage

Target creature you control gets +2/+0 and gains haste until end of turn. When that creature dies this turn, create a 2/2 white and blue Detective creature token.

Otherworldly Outburst

Target creature gets +1/+0 until end of turn. When that creature dies this turn, create a 3/2 colorless Eldrazi Horror creature token.

Dwarven Mine

({T}: Add {R}.)
Dwarven Mine enters the battlefield tapped unless you control three or more other Mountains.
When Dwarven Mine enters the battlefield untapped, create a 1/1 red Dwarf 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.

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Impact Tremors

Whenever a creature enters the battlefield under your control, Impact Tremors deals 1 damage to each opponent.

Goblin Instigator

When Goblin Instigator enters the battlefield, create a 1/1 red Goblin creature token.

Heat Shimmer

Create a token that's a copy of target creature, except it has haste and "At the beginning of the end step, exile this permanent."

Reckless Lackey

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

Blazing Crescendo

Target creature gets +3/+1 until end of turn.
Exile the top card of your library. Until the end of your next turn, you may play that card.

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.)

Krenko, Mob Boss

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

Young Pyromancer

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

Fire Diamond

Fire Diamond enters the battlefield tapped.
{T}: Add {R}.

Expedite

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Ornithopter of Paradise

Thought Vessel

Castle Embereth

Castle Embereth enters the battlefield tapped unless you control a Mountain.
{T}: Add {R}.
{1}{R}{R}, {T}: Creatures you control get +1/+0 until end of turn.

Brute Strength

Target creature gets +3/+1 and gains trample until end of turn.

Dualcaster Mage

Flash
When Dualcaster Mage enters the battlefield, copy target instant or sorcery spell. You may choose new targets for the copy.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Rograkh, Son of Rohgahh

First strike, menace, trample
Partner (You can have two commanders if both have partner.)

Hedron Crawler

{T}: Add {C}. ({C} represents colorless mana.)

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.

Dragon Fodder

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 Mogg War Marshal enters the battlefield or dies, create a 1/1 red Goblin creature token.

Samut's Sprint

Target creature gets +2/+1 and gains haste until end of turn. Scry 1.

Mana Geyser

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

Balduvian Rage

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

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.

Sudden Breakthrough

Traitorous Greed

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Add two mana of any one color. (The creature can attack and {T} this turn.)

Spark of Creativity

Choose target creature. Exile the top card of your library. You may have Spark of Creativity deal damage to that creature equal to the exiled card's mana value. If you don't, you may play that card until end of turn.