Goblin Trashmaster

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

Hellrider

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

Goblin Recruiter

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

Cavalcade of Calamity

Whenever a creature you control with power 1 or less attacks, Cavalcade of Calamity deals 1 damage to the player or planeswalker that creature is attacking.

Guild Artisan

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, you create two Treasure tokens." (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Hobgoblin Bandit Lord

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

Goblin Bombardment

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

Goblin King

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

Goblin Warchief

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

Goblin Chirurgeon

Sacrifice a Goblin: Regenerate target creature.

Skirk Prospector

Beetleback Chief

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

Goblin Instigator

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

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

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.

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Krenko, Mob Boss

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

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.

Treasure Nabber

Whenever an opponent taps an artifact for mana, gain control of that artifact until the end of your next turn.

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.

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.

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.