Species

As of the end of FreeSpace 2, there are four canon species in the FreeSpace universe.

Terrans - The Terrans, or Humans, are the most prominent race in the games, and the race of the player in all official FreeSpace titles to date.
Vasudans - A race of philosophers and warriors from a desert world, the Vasudans are adversaries in the early stages of FreeSpace 1, but firm allies by FreeSpace 2.
Shivans - A five-limbed, xenocidal alien race, the Shivans are the primary adversary in both FreeSpace 1 and 2.
Ancients - A mysterious, extinct species known only from ruins, the Ancients provided the Terran-Vasudan Alliance with the information that killed the Lucifer, and built the Knossos portal in Gamma Draconis.

Non Canon Species

The following information has not been confirmed by Volition and is therefore not canon for the FreeSpace universe.

Aesdherians - A species from the user-made Ancient-Shivan War campaign.
Aesir - A species from the user-made Twisted Infinities campaign.
Nightmares - A species originally created for the (now-cancelled) Reciprocity campaign.
Starborn - Superior, omnipotent and omnipresent creatures from MindGames.
Tiigran-Merisst - A species from the user-made Teeth of the Tiger campaign.
Vishnans - The 'Great Preservers;' counterparts to the Shivans in their role as the 'Great Destroyers.'