Shark attack for buccaneers---sharks buff them why not attack too, causes bleeding and immobilize
Rifling shot for musketeers more accurate and damaging
Lunge for Swashbucklers-attack from two squares away
Mercenary strike for Privateers-privateers sell their skills for gold. The player would enter an amount of their gold and damage would be based on how much they pay. The game would set a cap for this of course.
Destroying Angel for Witchdoctors-automatically revive with half health after being defeated once per battle.