Ruby Medallion

Red spells you cast cost {1} less to cast.

Obliterating Bolt

Obliterating Bolt deals 4 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

Goblin Instigator

When Goblin Instigator enters, create a 1/1 red Goblin creature token.

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.

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.

Bitter Reunion

When Bitter Reunion enters, you may discard a card. If you do, draw two cards.
{1}, Sacrifice Bitter Reunion: Creatures you control gain haste until end of turn.

Throne of the God-Pharaoh

At the beginning of your end step, each opponent loses life equal to the number of tapped creatures you control.

Fervor

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

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.

Raid Bombardment

Whenever a creature you control with power 2 or less attacks, Raid Bombardment deals 1 damage to the player or planeswalker that creature is attacking.

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.

Grenzo, Havoc Raiser

Whenever a creature you control deals combat damage to a player, choose one —
• Goad target creature that player controls.
• Exile the top card of that player's library. Until end of turn, you may cast that card and you may spend mana as though it were mana of any color to cast that spell.

Skullclamp

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

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Goblin Mountaineer

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)

Goblin War Drums

Creatures you control have menace. (They can't be blocked except by two or more creatures.)

Krenko, Mob Boss

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

Blood Moon

Goblin King

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

Siege-Gang Lieutenant

Lieutenant — At the beginning of combat on your turn, if you control your commander, create two 1/1 red Goblin creature tokens. Those tokens gain haste until end of turn.
{2}, Sacrifice a Goblin: Siege-Gang Lieutenant deals 1 damage to any target.

Ashnod's Altar

Kiki-Jiki, Mirror Breaker

Haste
{T}: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Gleeful Demolition

Destroy target artifact. If you controlled that artifact, create three 1/1 red Phyrexian Goblin creature tokens.

Sword of the Paruns

As long as equipped creature is tapped, tapped creatures you control get +2/+0.
As long as equipped creature is untapped, untapped creatures you control get +0/+2.
{3}: You may tap or untap equipped creature.
Equip {3}

Kyren Negotiations

Tap an untapped creature you control: Kyren Negotiations deals 1 damage to target player or planeswalker.

Legion Warboss

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
At the beginning of combat on your turn, create a 1/1 red Goblin creature token. That token gains haste until end of turn and attacks this combat if able.