Here are a few starters:

Shiver me timbers! 

Dead men tell no tales, now do they?

Ahoy, me Bucko!  Grab a grog.

Avast!  You slimey bilge rat.  Swab the deck!

Sail Ho!  Man-of-war off the starboard.  Ready the guns!

Argh!  It’s the black spot!

Prepare to visit Davy Jones’s locker!

Hornswaggle me, and you’ll lie in a dead man’s chest!

Blimey!  Me eyes have never seen so many doubloons in one chest?!

Ye scurvy dog.  Yar walk’n the plank for that!

All hands on deck!  Weigh anchor!  Put yar backs into it!

Smartly there, Mates.  Time to haul wind!

Hoist the Jolly Roger!  It’s time to pillage and plunder.  Arrrrrrrr!

It’s Cap’n Black Beard, the scourge of the seven seas!

Aye! The booty is buried off the Barbary Coast.

Flogging’s too good for him.  Keelhaul the dirty dog!

Hang ‘em from the yardarm and scuttle his ship!

Sing a shanty, me boys, “Yo-ho, yo-ho, a pirate’s life for me!”

Argh!  The albatross, tis a bad sign of the sea.

Handsomely now men, draw your cutlass and take no quarter!

Fire a shot across her bow.