Fireblast

You may sacrifice two Mountains rather than pay this spell's mana cost.
Fireblast deals 4 damage to any target.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Foundry Street Denizen

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

Mountain

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Inferno Fist

Enchant creature you control
Enchanted creature gets +2/+0.
{R}, Sacrifice Inferno Fist: Inferno Fist deals 2 damage to any target.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Shock

Vexing Devil

When Vexing Devil enters, any opponent may have it deal 4 damage to them. If a player does, sacrifice Vexing Devil.

Goblin Shortcutter

When Goblin Shortcutter enters, target creature can't block this turn.

Phoenix Chick

Flying, haste
Phoenix Chick can't block.
Whenever you attack with three or more creatures, you may pay {R}{R}. If you do, return Phoenix Chick from your graveyard to the battlefield tapped and attacking with a +1/+1 counter on it.