Mountain

Paragon of Fierce Defiance

Other red creatures you control get +1/+1.
{R}, {T}: Another target red creature you control gains haste until end of turn. (It can attack and {T} this turn.)

Staff of the Flame Magus

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

Thundering Giant

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

Seismic Strike

Seismic Strike deals damage to target creature equal to the number of Mountains you control.

Rummaging Goblin

Borderland Marauder

Whenever this creature attacks, it gets +2/+0 until end of turn.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Shivan Dragon

Flying
{R}: This creature gets +1/+0 until end of turn.

Furnace Whelp

Goblin Roughrider

Lava Axe

Lava Axe deals 5 damage to target player or planeswalker.

Cone of Flame

Cone of Flame deals 1 damage to any target, 2 damage to another target, and 3 damage to a third target.

Foundry Street Denizen

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