Mudbutton Cursetosser

As an additional cost to cast this spell, behold a Goblin or pay {2}. (To behold a Goblin, choose a Goblin you control or reveal a Goblin card from your hand.)
This creature can't block.
When this creature dies, destroy target creature an opponent controls with power 2 or less.

Boggart Bog

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Boggart Trawler

When this creature enters, exile target player's graveyard.

Boggart Trawler // Boggart Bog

Commercial District

({T}: Add {R} or {G}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Arena of Glory

This land enters tapped unless you control a Mountain.
{T}: Add {R}.
{R}, {T}, Exert this land: Add {R}{R}. If that mana is spent on a creature spell, it gains haste until end of turn. (An exerted permanent won't untap during your next untap step.)

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 this creature enters or dies, create a 1/1 red Goblin creature token.

Raucous Theater

({T}: Add {B} or {R}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Grub, Notorious Auntie

Menace
Whenever Grub attacks, you may blight 1. If you do, create a tapped and attacking token that's a copy of the blighted creature, except it has "At the beginning of the end step, sacrifice this token."
At the beginning of your first main phase, you may pay {B}. If you do, transform Grub.

Grub, Storied Matriarch

Menace
Whenever this creature enters or transforms into Grub, Storied Matriarch, return up to one target Goblin card from your graveyard to your hand.
At the beginning of your first main phase, you may pay {R}. If you do, transform Grub.

Grub, Storied Matriarch // Grub, Notorious Auntie

Taster of Wares

When this creature enters, target opponent reveals X cards from their hand, where X is the number of Goblins you control. You choose one of those cards. That player exiles it. If an instant or sorcery card is exiled this way, you may cast it for as long as you control this creature, and mana of any type can be spent to cast that spell.

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Wooded Foothills

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Sling-Gang Lieutenant

When this creature enters, create two 1/1 red Goblin creature tokens.
Sacrifice a Goblin: Target player loses 1 life and you gain 1 life.

Warren Instigator

Double strike
Whenever this creature deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield.

Birthing Ritual

At the beginning of your end step, if you control a creature, look at the top seven cards of your library. Then you may sacrifice a creature. If you do, you may put a creature card with mana value X or less from among those cards onto the battlefield, where X is 1 plus the sacrificed creature's mana value. Put the rest on the bottom of your library in a random order.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Munitions Expert

Flash
When this creature enters, you may have it deal damage to target creature or planeswalker equal to the number of Goblins you control.

Mountain

Blood Crypt

({T}: Add {B} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.