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.

Goblin Piledriver

Protection from blue (This creature can't be blocked, targeted, dealt damage, or enchanted by anything blue.)
Whenever this creature attacks, it gets +2/+0 until end of turn for each other attacking Goblin.

Mountain

Fanatical Firebrand

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}, Sacrifice this creature: It deals 1 damage to any target.

Krenko, Mob Boss

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

Goblin Recruiter

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

Renegade Tactics

Target creature can't block this turn.
Draw a card.

Bloodline Pretender

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on this creature.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Forgotten Cave

This land enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Skirk Prospector

Muxus, Goblin Grandee

When Muxus enters, reveal the top six cards of your library. Put all Goblin creature cards with mana value 5 or less from among them onto the battlefield and the rest on the bottom of your library in a random order.
Whenever Muxus attacks, it gets +1/+1 until end of turn for each other Goblin you control.

Goblin Chieftain

Haste (This creature can attack and {T} as soon as it comes under your control.)
Other Goblin creatures you control get +1/+1 and have haste.

Samut's Sprint

Target creature gets +2/+1 and gains haste until end of turn. Scry 1.

Foundry Street Denizen

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

Goblin Matron

When this creature enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Goblin Motivator

{T}: Target creature gains haste until end of turn. (It can attack and {T} this turn.)

Emblem of the Warmind

Enchant creature you control
Creatures you control have haste.

Massive Raid

Massive Raid deals damage to any target equal to the number of creatures you control.

Goblin Lackey

Whenever this creature deals damage to a player, you may put a Goblin permanent card from your hand onto the battlefield.

Hobgoblin Bandit Lord

Other Goblins you control get +1/+1.
{R}, {T}: This creature deals damage equal to the number of Goblins that entered the battlefield under your control this turn to any target.

You See a Pair of Goblins

Choose one —
• Charge Them — Creatures you control get +2/+0 until end of turn.
• Befriend Them — Create two 1/1 red Goblin creature tokens.