Thinking possible alien races, my mind went to the RPG Vampire: The Masquerade
with its Clans, each an archetype--with surprising parallels to some species in Star Trek
. For example, the supremely organized and ruthless Tremere remind me very much of the Cardassians. Likewise the honor-bound Brujah are somewhat Klingon-esque, the uber-practical and ambitious Ventrue echo the Romulans. Shape-shifting Tzimiscze who see themselves as higher being than everyone else, crafting whole new species for their own ends--sound rather like the Founders?
Looking to those very archetypes, one can use the same archetypes to design some other alien race. The Toreador, for example, embody the idea of life-as-art, who literally look upon artistic achievement the way Ferengi see profit (even though of course many of them have no real talent at all). Likewise the Malkavians have let go of linear thinking, becoming in the process oracles of strange power (they think nowhere near anyplace that has ever heard of a box).
Just a thought...