Mountain

Bloodmark Mentor

Red creatures you control have first strike.

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.

Goblin Piledriver

Protection from blue (This creature can't be blocked, targeted, dealt damage, or enchanted by anything blue.)
Whenever Goblin Piledriver attacks, it gets +2/+0 until end of turn for each other attacking Goblin.

Goblin Trashmaster

Other Goblins you control get +1/+1.
Sacrifice a Goblin: Destroy target artifact.

Gempalm Incinerator

Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)
When you cycle Gempalm Incinerator, you may have it deal X damage to target creature, where X is the number of Goblins on the battlefield.

Dark-Dweller Oracle

{1}, Sacrifice a creature: Exile the top card of your library. You may play that card this turn. (You still pay its costs. You can play a land this way only if you have an available land play remaining.)

Kiki-Jiki, Mirror Breaker

Haste
{T}: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

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.

Vanquisher's Banner

As Vanquisher's Banner enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

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.

Krenko, Mob Boss

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

Goblin Warchief

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

Legion Loyalist

Haste
Battalion — Whenever Legion Loyalist and at least two other creatures attack, creatures you control gain first strike and trample until end of turn and can't be blocked by creature tokens this turn.

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.

Ogre Battledriver

Whenever another creature enters the battlefield under your control, that creature gets +2/+0 and gains haste until end of turn. (It can attack and {T} this turn.)

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.

Battle Squadron

Flying
Battle Squadron's power and toughness are each equal to the number of creatures you control.

Goblin Bushwhacker

Kicker {R} (You may pay an additional {R} as you cast this spell.)
When Goblin Bushwhacker enters the battlefield, if it was kicked, creatures you control get +1/+0 and gain haste until end of turn.