Mana Geyser

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

Goblinslide

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

Subterranean Scout

When Subterranean Scout enters, target creature with power 2 or less can't be blocked this turn.

Goblin Brawler

First strike
Goblin Brawler can't be equipped.

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 Goblin Rabblemaster attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Hall of Triumph

As Hall of Triumph enters, choose a color.
Creatures you control of the chosen color get +1/+1.

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Goblin War Paint

Enchant creature
Enchanted creature gets +2/+2 and has haste.

Lavastep Raider

{2}{R}: Lavastep Raider gets +2/+0 until end of turn.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Mountain

Hammer of Purphoros

Creatures you control have haste.
{2}{R}, {T}, Sacrifice a land: Create a 3/3 colorless Golem enchantment artifact creature token.

Iron Myr

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Flurry of Horns

Create two 2/3 red Minotaur creature tokens with haste.

Magma Spray

Magma Spray deals 2 damage to target creature. If that creature would die this turn, exile it instead.

Trumpet Blast

Attacking creatures get +2/+0 until end of turn.

Staff of the Flame Magus

Whenever you cast a red spell or a Mountain you control enters, you gain 1 life.

Torch Slinger

Kicker {1}{R} (You may pay an additional {1}{R} as you cast this spell.)
When Torch Slinger enters, if it was kicked, it deals 2 damage to target creature.

Mardu Scout

Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Screaming Fury

Target creature gets +5/+0 and gains haste until end of turn.

Kuldotha Ringleader

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Kuldotha Ringleader attacks each combat if able.

Rite of Flame

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Goblin Heelcutter

Whenever Goblin Heelcutter attacks, target creature can't block this turn.
Dash {2}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Boggart Brute

Menace (This creature can't be blocked except by two or more creatures.)

Foundry Street Denizen

Whenever another red creature you control enters, Foundry Street Denizen gets +1/+0 until end of turn.

Goblin Sky Raider

Flying (This creature can't be blocked except by creatures with flying or reach.)

Two-Headed Cerberus

Double strike (This creature deals both first-strike and regular combat damage.)

Flamespeaker's Will

Enchant creature you control
Enchanted creature gets +1/+1.
Whenever enchanted creature deals combat damage to a player, you may sacrifice Flamespeaker's Will. If you do, destroy target artifact.

Infectious Bloodlust

Enchant creature
Enchanted creature gets +2/+1, has haste, and attacks each combat if able.
When enchanted creature dies, you may search your library for a card named Infectious Bloodlust, reveal it, put it into your hand, then shuffle.

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.)