Medusans, Ithenites, Andorians
The Medusans are the first non-corporeal species to make official contact and work with the Federation. Unlike other non-corporeal beings, they are not that much advanced compared to humans, and have only had space travel ability in the last 200 years. Looking at a Medusan directly will cause one to go insane, so they must remain in their energy forms within a specialized box, and they may leave when those around are wearing special visors to protect themselves.
The Ithenites are an advanced civilization capable of reaching speeds up to Warp 9. They are heavily secretive, but do make trips when given transportation from another culture. They often hire freighters, such as the Yorktown, to transport them to a select locale such as Risa or Betazed. They are diminuitive, usually three to four feet in height, and wear a fez-like hat often.
The Andorians are a warrior race and member of the Federation. In recent years, many have believed that the Federation has become weak and Andorian culture is being wiped out. When rumors of Andorian-Tellarite breeding was released, many Andorians joined various terrorist groups, and often attack Federation ships with old Kumari-class freighters. The roaming Andorian terrorists are often seen on the Yorktown freight run and they must try to avoid them.