Mountain

Thrill of Possibility

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

Goblin Wardriver

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

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.

Krenko, Mob Boss

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

Castle Embereth

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

Sol Ring

Mob Justice

Mob Justice deals damage to target player or planeswalker equal to the number of creatures you control.

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Goblin War Strike

Goblin War Strike deals damage to target player or planeswalker equal to the number of Goblins you control.

Skirk Prospector

Command Tower

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

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Goblin Instigator

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

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Goblin Warchief

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

Goblin Matron

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

Forgotten Cave

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

Impact Tremors

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

Goblin War Drums

Creatures you control have menace. (They can't be blocked except by two or more creatures.)

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Krenko's Enforcer

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)