Rummaging Goblin

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Goblin Piledriver

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

Skirk Fire Marshal

Protection from red
Tap five untapped Goblins you control: Skirk Fire Marshal deals 10 damage to each creature and each player.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Skirk Prospector

Skirk Commando

Whenever Skirk Commando deals combat damage to a player, you may have it deal 2 damage to target creature that player controls.
Morph {2}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Goblin Guide

Haste
Whenever Goblin Guide attacks, defending player reveals the top card of their library. If it's a land card, that player puts it into their hand.

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Staff of Domination

{1}: Untap Staff of Domination.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Witty Roastmaster

Alliance — Whenever another creature you control enters, Witty Roastmaster deals 1 damage to each opponent.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Scrap Welder

{T}, Sacrifice an artifact with mana value X: Return target artifact card with mana value less than X from your graveyard to the battlefield. It gains haste until end of turn.

Akki Ember-Keeper

Whenever a nontoken modified creature you control dies, create a 1/1 colorless Spirit creature token. (Equipment, Auras you control, and counters are modifications.)

Ashnod's Altar

Change of Fortune

Discard your hand, then draw a card for each card you've discarded this turn.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Karn, the Great Creator

Activated abilities of artifacts your opponents control can't be activated.
+1: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.
−2: You may reveal an artifact card you own from outside the game or choose a face-up artifact card you own in exile. Put that card into your hand.

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Frenzied Goblin

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

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Flame Slash

Flame Slash deals 4 damage to target creature.

Conspicuous Snoop

Play with the top card of your library revealed.
You may cast Goblin spells from the top of your library.
As long as the top card of your library is a Goblin card, Conspicuous Snoop has all activated abilities of that card.

Krenko, Mob Boss

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

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Tuktuk the Explorer

Haste
When Tuktuk the Explorer dies, create Tuktuk the Returned, a legendary 5/5 colorless Goblin Golem artifact creature token.

Magus of the Moon

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Reforge the Soul

Each player discards their hand, then draws seven cards.
Miracle {1}{R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Sol Ring

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Goro-Goro, Disciple of Ryusei

{R}: Creatures you control gain haste until end of turn.
{3}{R}{R}: Create a 5/5 red Dragon Spirit creature token with flying. Activate only if you control an attacking modified creature. (Equipment, Auras you control, and counters are modifications.)