"Lungs full of sea air and a hold full of loot. Ah, what a life!"

Corsair Captain

When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Other Pirates you control get +1/+1.

Foundations

The Lost Caverns of Ixalan Commander

When Corsair Captain enters the battlefield, create a Treasure token.
Other Pirates you control get +1/+1.

Jumpstart

Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to Pirates you control may become lethal if Corsair Captain leaves the battlefield during that turn.