There are two types of pirates in One Piece, but the terms were only in the original Romance Dawn chapter. They have not been mentioned in the current version of One Piece and it is doubtful they still apply to it.
Types of PiratesEdit
First mentioned in Romance Dawn V.1, the two main types of pirate are Peace Main (ピースメイン Pīsu Mein?)and Morganeer (モーガニア Mōgania?). These terms were once again mentioned in Romance Dawn V.2, and in Wanted! Chapter 5, however they are not mentioned in One Piece itself. This is largely because most pirates are a combination of both peace main and morganeer. Even the final version, a certain amount of pirates display these original concepts, though the actual terms are no longer used.
There is also another kind of pirates, known as "rookie" pirates, which the Straw Hats fell under before the timeskip. In fact, all the so-called "Super Rookies", along with the Bellamy Pirates from two years prior the current timeline are considered to be rookies. It is unknown what qualifies a person or crew to be a rookie though the word generally means that they are new-comers or new recruits. This may mean that these pirates have only been active for a short time and are relatively new, though there is a case of a pirate being considered a rookie even after three years.
Female pirates, though unusual, are by no means rare. The reason for this may stem from the old superstition that women on a ship is bad luck, but also possibly due to the fact that pirates are unsavory characters. More often than not, the women tend to be the captains of their crew, with certain exceptions, like with the Straw Hats, the Foxy Pirates, and the Whitebeard Pirates.
Described in Romance Dawn Version 1, a peace main is a pirate who goes on adventures and does not really care about amassing treasure or fighting other pirates. Luffy, Brook, Shanks, and Whitebeard are all good examples of pirates based on the old peace mains (along with their respective crews) from Romance Dawn. That is not to say that they will not steal treasure from others if it is there and the chance is open, but their primary goal is usually not to own it and greed is generally not their motivation. More often than not, a peace main pirate sees his or her own crew as their most valuable treasure.
Some pirates start out as peace mains but may have a life changing experience, possibly a great loss or general corruption over time, and become more like a morganeer. The best example of this is Crocodile, who is said to have been very much like Luffy in his youth, or Gekko Moriah, who stated that he was exactly like Luffy until he lost his crew in the New World. Peace mains have been described in Wanted! Chapter 5 as a pirate that goes on adventures funding themselves on the spoils of battles with morganeers.
The morganeer fight for treasure and personal ambition. They are greedy and love to fight just to cause other people pain and misery. Most of the other pirates Luffy and his crew meet are morganeers. Luffy dislikes them and only wants to recruit peace main pirates. Even in the beginning storyline, most One Piece villains are based on the concept of morganeer pirates, such as Buggy, Kuro, and Don Krieg. The peace main pirates however, only steal from them, so it is safe to say that the relations between the two are not the best.
Morganeer pirates do not see their crew as a valuable asset to them and will easily kill them for opposing them as demonstrated by Don Krieg. Kuro also did not think twice about slaughtering his own underlings, and the only sympathy he showed towards his crew was because Luffy stopped him so that they would not have to suffer. Luffy was disgusted to see Kuro slashing his own men half to death.
Also, a majority of the morganeer type pirates shown in One Piece do not dream at all, and if they do, it is about achieving world domination or something along the lines of that. There are only a few morganeer pirate captains who have an amiable relationship with their crew like Vander Decken, IX, Brownbeard, Arlong, Buggy, and even Blackbeard himself.