Mountain

Impact Tremors

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

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Crookshank Kobolds

Kobolds of Kher Keep

Crimson Kobolds

Keep Watch

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Roar of the Crowd

Choose a creature type. Roar of the Crowd deals damage to any target equal to the number of permanents you control of the chosen type.

Betrothed of Fire

Enchant creature
Sacrifice an untapped creature: Enchanted creature gets +2/+0 until end of turn.
Sacrifice enchanted creature: Creatures you control get +2/+0 until end of turn.

Goblin Bushwhacker

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

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Mob Justice

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