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.

Ring of Valkas

Equipped creature has haste. (It can attack and {T} no matter when it came under your control.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's red.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Mask of Immolation

When Mask of Immolation enters, create a 1/1 red Elemental creature token, then attach Mask of Immolation to it.
Equipped creature has "Sacrifice this creature: It deals 1 damage to any target."
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Gempalm Incinerator

Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)
When you cycle Gempalm Incinerator, you may have it deal X damage to target creature, where X is the number of Goblins on the battlefield.

Forge of Heroes

{T}: Add {C}.
{T}: Choose target commander that entered this turn. Put a +1/+1 counter on it if it's a creature and a loyalty counter on it if it's a planeswalker.

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Snow-Covered Mountain

Bravado

Enchant creature
Enchanted creature gets +1/+1 for each other creature you control.

Outnumber

Outnumber deals damage to target creature equal to the number of creatures you control.

Skirk Prospector

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Goblin Rally

Create four 1/1 red Goblin creature tokens.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Mountain

Goblin War Drums

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

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Goblin Ringleader

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Goblin Ringleader enters, reveal the top four cards of your library. Put all Goblin cards revealed this way into your hand and the rest on the bottom of your library in any order.

Goblin Matron

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

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Mogg Raider

Sacrifice a Goblin: Target creature gets +1/+1 until end of turn.

Hero's Blade

Equipped creature gets +3/+2.
Whenever a legendary creature you control enters, you may attach Hero's Blade to it.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Krenko, Tin Street Kingpin

Whenever Krenko, Tin Street Kingpin attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power.

Stoneforge Masterwork

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}

Battle Squadron

Flying
Battle Squadron's power and toughness are each equal to the number of creatures you control.

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Spellbook

Heraldic Banner

As Heraldic Banner enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Massive Raid

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

Goblin Trashmaster

Other Goblins you control get +1/+1.
Sacrifice a Goblin: Destroy target artifact.

Desert of the Fervent

Desert of the Fervent enters tapped.
{T}: Add {R}.
Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)

Goblin Lookout

{T}, Sacrifice a Goblin: Goblin creatures get +2/+0 until end of turn.

Hazoret's Monument

Red creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, you may discard a card. If you do, draw a card.

Red Elemental Blast

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

Sigil of Valor

Whenever equipped creature attacks alone, it gets +1/+1 until end of turn for each other creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Iron Myr

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Hedron Archive: Draw two cards.

Looming Spires

Looming Spires enters tapped.
When Looming Spires enters, target creature gets +1/+1 and gains first strike until end of turn.
{T}: Add {R}.

Smoldering Crater

Smoldering Crater enters tapped.
{T}: Add {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Goblin Chirurgeon

Sacrifice a Goblin: Regenerate target creature.

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.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Goblin War Strike

Goblin War Strike deals damage to target player or planeswalker equal to the number of Goblins you control.

Curse of Bloodletting

Enchant player
If a source would deal damage to enchanted player, it deals double that damage to that player instead.

Goblin Champion

Haste
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Empty the Warrens

Create two 1/1 red Goblin creature tokens.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Brute Force

Target creature gets +3/+3 until end of turn.

Goblin Wardriver

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)

Goblin Oriflamme

Attacking creatures you control get +1/+0.

Beetleback Chief

When Beetleback Chief enters, create two 1/1 red Goblin creature tokens.

Pashalik Mons

Whenever Pashalik Mons or another Goblin you control dies, Pashalik Mons deals 1 damage to any target.
{3}{R}, Sacrifice a Goblin: Create two 1/1 red Goblin creature tokens.

Mana Geyser

Add {R} for each tapped land your opponents control.

Sol Ring

Sword of Vengeance

Equipped creature gets +2/+0 and has first strike, vigilance, trample, and haste.
Equip {3}

Goblin Warchief

Goblin spells you cast cost {1} less to cast.
Goblins you control have haste.

Opal Palace

{T}: Add {C}.
{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

Forgotten Cave

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

Goblin Instigator

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

Goblin Chainwhirler

First strike
When Goblin Chainwhirler enters, it deals 1 damage to each opponent and each creature and planeswalker they control.

Last-Ditch Effort

Sacrifice any number of creatures. Last-Ditch Effort deals that much damage to any target.

Seething Song

War Cadence

{X}{R}: This turn, creatures can't block unless their controller pays {X} for each blocking creature they control.

Fists of the Anvil

Target creature gets +4/+0 until end of turn.

Krenko, Mob Boss

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

Reckless Bushwhacker

Surge {1}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Haste
When Reckless Bushwhacker enters, if its surge cost was paid, other creatures you control get +1/+0 and gain haste until end of turn.

Dragon Fodder

Chancellor of the Forge

You may reveal this card from your opening hand. If you do, at the beginning of the first upkeep, create a 1/1 red Phyrexian Goblin creature token with haste.
When Chancellor of the Forge enters, create X 1/1 red Phyrexian Goblin creature tokens with haste, where X is the number of creatures you control.

Battle Hymn

Brass Squire

{T}: Attach target Equipment you control to target creature you control.

Goblin Burrows

{T}: Add {C}.
{1}{R}, {T}: Target Goblin creature gets +2/+0 until end of turn.

Kitesail

Equipped creature gets +1/+0 and has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Reckless One

Haste
Reckless One's power and toughness are each equal to the number of Goblins on the battlefield.

Goblin Motivator

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