Pirates

Pirates come in different styles and ways with acts such as plunder, murder, stealing, piracy, kidnapping, and/or law-breaking usually for financial purposes.

Some can be leaders of a crew that sees everything the same way, but may be betrayed or "mutinied against" by their plunder-buddies.

Military Villains associated with naval warfare can go under this category.

Since piracy as it was practiced in classical times is romanticized in fiction many works feature Good Pirates as well as evil ones.