Mountain

Hunted Phantasm

Hunted Phantasm can't be blocked.
When Hunted Phantasm enters, target opponent creates five 1/1 red Goblin creature tokens.

Goblin Gathering

Create a number of 1/1 red Goblin creature tokens equal to two plus the number of cards named Goblin Gathering in your graveyard.

Tivadar of Thorn

First strike, protection from red
When Tivadar of Thorn enters, destroy target Goblin.

Frenzied Goblin

Whenever this creature attacks, you may pay {R}. If you do, target creature can't block this turn.

Lightmine Field

Whenever one or more creatures attack, Lightmine Field deals damage to each of those creatures equal to the number of attacking creatures.

Goblin Shortcutter

When Goblin Shortcutter enters, target creature can't block this turn.

Goblin Sledder

Sacrifice a Goblin: Target creature gets +1/+1 until end of turn.

Auntie's Snitch

Auntie's Snitch can't block.
Prowl {1}{B} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Goblin or Rogue.)
Whenever a Goblin or Rogue you control deals combat damage to a player, if Auntie's Snitch is in your graveyard, you may return Auntie's Snitch to your hand.

Kuon's Essence

At the beginning of each player's upkeep, that player sacrifices a creature of their choice.

Kuon, Ogre Ascendant

At the beginning of the end step, if three or more creatures died this turn, flip Kuon, Ogre Ascendant.

Kuon, Ogre Ascendant // Kuon's Essence

Goblin Arsonist

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Boompile

{T}: Flip a coin. If you win the flip, destroy all nonland permanents.

Goblin Instigator

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

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.

Lightning Crafter

Champion a Goblin or Shaman (When this enters, sacrifice it unless you exile another Goblin or Shaman you control. When this leaves the battlefield, that card returns to the battlefield.)
{T}: Lightning Crafter deals 3 damage to any target.

Fissure Wizard

When Fissure Wizard enters, you may discard a card. If you do, draw a card.

Mudbrawler Cohort

Haste
Mudbrawler Cohort gets +1/+1 as long as you control another red creature.

Bag of Tricks

{4}{G}, {T}: Roll a d8. Reveal cards from the top of your library until you reveal a creature card with mana value equal to the result. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Goblin Trailblazer

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

Goblin War Paint

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

Redcap Raiders

Whenever Redcap Raiders attacks, you may tap an untapped non-Human creature you control. If you do, Redcap Raiders gets +1/+1 and gains trample until end of turn.

Raging Goblin

Haste (This creature can attack and {T} as soon as it comes under your control.)

Riot Piker

First strike
Riot Piker attacks each combat if able.

Foundry Street Denizen

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