From Gurps Space

Dominant
One or more species may dominate others; their power may be military (conquerors or peace keepers) or economic (manufacturers, traders, or explorers). Dominant alien civilizations are well known near their regions of space. The opposite is subordinate species that are dominated by others. Humans are often a dominant species.

Common
A race that is older, fast-breeding, or aggressive in exploration may be encountered often. Such races are also well-known in their localities, regardless of dominance. The opposite is rare; such races may be new to interstellar civilization, secretive, or slow-breeding.

Exotic
Races may be well-known because they have odd customs, bizarre reputations, unusual biology, or control of a particular technology.

Advanced
Some races might have a higher tech level than the rest of the campaign setting- possibly even so advanced as to seem like gods compared to everyone else. They may use their power to help "lesser" civilizations, or to conquer and oppress them. The opposite is primitive, a race that is technologically backward.