Star Trek Voyager RPG d20 System

Romulans
An Enigmatic race whose homeworld is somewhere in the Beta Quadrant. While no one has ever
actually seen a Romulan face to face (yet) many have fallen prey to Romulan Starships. If a
Romulan Starship Captain feels that they cannot win a battle they will scuttle their ship so as to
not allow another species access to their genetic code and their technology. Romulans are
constantly attempting to create distrust and conflict between the other species of the sector.
Rumor has it that they have an outpost in the remote system called Algeron.
http://en.memory-alpha.org/wiki/Romulan
Cardassians
The Cardassians were a humanoid species from the Alpha Quadrant. They were native to
the planet Cardassia Prime, capital world of the Cardassian Union. Known throughout the
Alpha Quadrant for their ruthlessness, the Cardassians became one of the greatest enemies
of the United Federation of Planets and Klingon Empire when they joined the Dominion in
2373. Their xenophobic attitude towards other species was well established throughout the
quadrant after the Setlik III massacre during the Cardassian War, as well as when their
atrocities during the Occupation of Bajor were revealed after their withdrawal in 2369.
http://en.memory-alpha.org/wiki/Cardassian
More Species here:
http://startrekd20.wikia.com/wiki/Playable_Species