The Corvo: Rampaging capitalists. Lovers of profit and technology. The most outspread of all the races, as they need to expand quickly to feed the unstoppable machine that is their dominions, the Corvosphere. If you have money, your quality of life will be without equal. If you don't, you'll be the lowest of the low. Corvo-tech is the most advanced in Known Space.
The Iz'kal. Mildly telepathic humanoids, evolved from marine mammals. A civilisation with virtually no lying and very little crime. Their culture, called The State, is very eco-aware, and expands keeping a balance between technology and nature. Masters of genetic manipulation, embryos are changed to perform their future jobs whilst still in uterus. If you don't conform, you'll have your whole race against you.
The Humans: Mankind self destructed in the fires of WWIII. When the Corvo arrived, they had very little effort annexing Earth. Humans would never again have a big civilisation, but through the Corvo, they moved out into Known Space as elite mercenaries. Most Corvo ships have one or two humans in cryo, for defence. Their services are highly sought by all races. Most humans are genetically sterilised by the Corvo, as a condition of contract off-Earth, to avoid having a highly trained growing population within their borders.
The Raag: Small but strong humanoids. Their homeworld is a frozen wasteland. After centuries of slavery, they rose up and wiped out their former masters, keeping huge amounts of their tech. The Raag now roam Known Space in their Ice Fortresses, looking for resources, as their Enginseers study their former slavers' tech. Ruthless towards enemies, most clans exist in a state of perpetual warfare. Rare is the Raag that perishes of natural causes. The biggest clans are the Kimora, the Eferi, the Velada, the Noteri and the Jino.
Ravagers. Origin: unknown. Purpose: unknown. A hive mind of countless organic obscenities intent on absorbing all living matter. 2 know planets dead, countless smaller incursions into Known Space. Never forget: the Queens never spend calories without a purpose.