Goblin Trailblazer

Menace (This creature can't be blocked except by two or more creatures.)

Spyglass Siren

Flying
When Spyglass Siren enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Malcolm, Keen-Eyed Navigator

Flying
Whenever one or more Pirates you control deal damage to your opponents, you create a Treasure token for each opponent dealt damage. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Partner (You can have two commanders if both have partner.)

Fanatical Firebrand

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}, Sacrifice this creature: It deals 1 damage to any target.

Lightning-Rig Crew

{T}: Lightning-Rig Crew deals 1 damage to each opponent.
Whenever you cast a Pirate spell, untap Lightning-Rig Crew.

Reckless Lackey

First strike, haste
{2}{R}, Sacrifice Reckless Lackey: Draw a card and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Goblin Tomb Raider

As long as you control an artifact, Goblin Tomb Raider gets +1/+0 and has haste.

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Departed Deckhand

When Departed Deckhand becomes the target of a spell, sacrifice it.
Departed Deckhand can't be blocked except by Spirits.
{3}{U}: Another target creature you control can't be blocked this turn except by Spirits.

Dargo, the Shipwrecker

As an additional cost to cast this spell, you may sacrifice any number of artifacts and/or creatures. This spell costs {2} less to cast for each permanent sacrificed this way and {2} less to cast for each other artifact or creature you've sacrificed this turn.
Trample
Partner (You can have two commanders if both have partner.)