Frenzied Goblin

Whenever Frenzied Goblin attacks, you may pay {R}. If you do, target creature can't block this turn.

Mountain

Boggart Shenanigans

Whenever another Goblin you control is put into a graveyard from the battlefield, you may have Boggart Shenanigans deal 1 damage to target player or planeswalker.

Mogg War Marshal

Echo {1}{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 Mogg War Marshal enters or dies, create a 1/1 red Goblin creature token.

Krenko's Enforcer

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Goblin Grenade

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

Hellraiser Goblin

Creatures you control have haste and attack each combat if able.

Goblin Heelcutter

Whenever Goblin Heelcutter 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.)

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Goblin Shortcutter

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

Ghostfire

Ghostfire is colorless.
Ghostfire deals 3 damage to any target.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

The Peregrine Dynamo

Haste
{1}, {T}: Copy target activated or triggered ability you control from another legendary source that's not a commander. You may choose new targets for the copy. (Mana abilities can't be targeted.)

Foundry Street Denizen

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

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.

Tarfire

Goblin Dark-Dwellers

Menace
When Goblin Dark-Dwellers enters, you may cast target instant or sorcery card with mana value 3 or less from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.