There are some, I'll cover a few here and see if anyone else thinks of any to add -
There are the F'eelines, that some are asking to see graphically represented in ships. They are rumored to be close to attaining the status of new avatar users. They like to attack the controls of starships, at the most annoying times, although most get away with it. Often rumored to chase vermin, eat crap, and have long tails. Not normally harmful, but can be trained by expert pilots. Nearly forgot, four legged.
Then there are the D'ipp Sheets - these guys fly around at engineer bases and near to populated space, to sneak up on unsuspecting commanders, where they cause damage by hitting, or ramming with their giant e-wangs. Largely humanoid, but with a great number of character defects, amongst their hideous body growths. Often mistaken for hicks. Will respond to arguments about game modes, and often set about each other due to lack of food.
I've also heard of the Castout Captains - commonly flying cruise ships around core systems, shouting about percentiles and things. They are rumored to like Fish Fingers, have big white beards, and be tied to corporate fishmongers. Mostly humanoid. Some are rumored to like children, just that little bit too much, if you know what I mean? If you meet them, refer to them as Captain, or make the universal greeting sound to grant yourself free passage - shouting YARRRRRRRR normally works.
I've heard of a group of aliens that used to be seen more than now, due to recent updates. These are again humanoid, and very spiritual in their nature. The Recovering Alcoholic Revenants, are normally found in big population systems, often in Orca analogues. They perform shotgun weddings for inbred humans, and this is where you'll meet them. They have dangerous psychic powers, making the bride at these weddings repeat the same overused lines far too often, up in local comms. Like the F'eelines, they wear collars, but for a different reason, and have strange links to the Castout Captains in terms of their affiliation to young humans. Mostly harmless bipedal humanoids, often seen in dark coloured dresses, speaking in Irish accents, and saying things to do with being "part of his plan" a lot - we presume from research that He is Braben. Be careful challenging them to a drinking contest, these guys have skills.
If I think of any other ones, I'll come back over. Hope this helps you out.
The Hat