It would be cool if you could find illager pirate boats. After all, illagers are raiders, too, just like pirates. Inside the boats there is many things:
all kinds of stuff from the ships they sunk(shipwrecks)
Wandering trader trapped in a prison(pirates attack trading ships)
lots of loot
And if you free the wandering trader and kill all the pillagers, he will give you a discount.
The boat should be made of dark oak, and one of the sails should have a pillager face on it, just like the staircase at the mansion