Electrickery

Electrickery deals 1 damage to target creature you don't control.
Overload {1}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Sparksmith

{T}: This creature deals X damage to target creature and X damage to you, where X is the number of Goblins on the battlefield.

Gorilla Shaman

{X}{X}{1}: Destroy target noncreature artifact with mana value X.

Goblin Cohort

This creature can't attack unless you've cast a creature spell this turn.

Jackal Familiar

This creature can't attack or block alone.

Valley Dasher

Haste
This creature attacks each combat if able.

Foundry Street Denizen

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

Flaring Pain

Damage can't be prevented this turn.
Flashback {R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mudbrawler Cohort

Haste
This creature gets +1/+1 as long as you control another red creature.

Flame Slash

Flame Slash deals 4 damage to target creature.

Burning-Tree Emissary

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Mountain

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

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.

Mogg Conscripts

Goblin Grenade

As an additional cost to cast this spell, sacrifice a Goblin.
Goblin Grenade deals 5 damage to any target.

Goblin Heelcutter

Whenever this creature attacks, target creature can't block this turn.
Dash {2}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)