Mountain

Kolaghan Stormsinger

Haste
Megamorph {R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Kolaghan Stormsinger is turned face up, target creature gains haste until end of turn.

Emberwilde Augur

Sacrifice Emberwilde Augur: It deals 3 damage to target player or planeswalker. Activate only during your upkeep.

Carbonize

Carbonize deals 3 damage to any target. If it's a creature, it can't be regenerated this turn, and if it would die this turn, exile it instead.

Keldon Champion

Haste
Echo {2}{R}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Keldon Champion enters, it deals 3 damage to target player or planeswalker.

Infectious Bloodlust

Enchant creature
Enchanted creature gets +2/+1, has haste, and attacks each combat if able.
When enchanted creature dies, you may search your library for a card named Infectious Bloodlust, reveal it, put it into your hand, then shuffle.

Furnace Scamp

Whenever Furnace Scamp deals combat damage to a player, you may sacrifice it. If you do, Furnace Scamp deals 3 damage to that player.

Brazen Scourge

Chandra's Pyrohelix

Chandra's Pyrohelix deals 2 damage divided as you choose among one or two targets.