Goblin Elite Infantry

Whenever Goblin Elite Infantry blocks or becomes blocked, it gets -1/-1 until end of turn.

Volcanic Dragon

Goblin Tinkerer

{R}, {T}: Destroy target artifact. That artifact deals damage equal to its mana value to Goblin Tinkerer.

Goblin Swine-Rider

Whenever Goblin Swine-Rider becomes blocked, it deals 2 damage to each attacking creature and each blocking creature.

Keeper of Kookus

{R}: Keeper of Kookus gains protection from red until end of turn.

Incinerate

Incinerate deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.

Goblin Scouts

Create three 1/1 red Goblin Scout creature tokens with mountainwalk. (They can't be blocked as long as defending player controls a Mountain.)

Goblin King

Other Goblins get +1/+1 and have mountainwalk.

Mob Mentality

Enchant creature
Enchanted creature has trample.
Whenever all non-Wall creatures you control attack, enchanted creature gets +X/+0 until end of turn, where X is the number of attacking creatures.

Mountain

Goblin Grenade

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

Flame Elemental

{R}, {T}, Sacrifice Flame Elemental: It deals damage equal to its power to target creature.

Song of Blood

Mill four cards. Whenever a creature attacks this turn, it gets +1/+0 until end of turn for each creature card put into your graveyard this way.

Goblin Balloon Brigade

{R}: Goblin Balloon Brigade gains flying until end of turn.

Goblin Recruiter

When Goblin Recruiter enters, search your library for any number of Goblin cards, reveal them, then shuffle and put those cards on top in any order.

Chaos Charm

Choose one —
• Destroy target Wall.
• Chaos Charm deals 1 damage to target creature.
• Target creature gains haste until end of turn.