Basically, get some races or nations from popular science fiction-ish things (eg. the Ur-Quan, the Irken Empire and the island of Genosha), stick them in a forum (ie, here) and see what happens (eg. hilarity, happy fun times).
Somebody go get Pack. I lay claim to the space Greeks, and Ulysses’ beard.
Flipping a coin between Wraith and Asgard…
I call the Daleks. https://groups.tapatalk-cdn.com/smilies/52127/1536592188.0653-smiley.gif?ttinline=true
ROFL! Wish I read more sci-fi!
I may or may not jump into the plot with a certain band of bounty hunters aboard the good 'ol Bebop. Maybe they’ll become mercenaries for the highest bidder. 
…If you haven’t watched Cowboy Bebop, do so now. Yes, now, whatever else can wait. Unless you’re baking cookies, then finish that and then go watch Cowboy Bebop. While eating cookies. Mmm… cookies…
… proceed.
Sci-fi, hmm? Alright. Emotionally-crippled Darth Vader, I choose you!
I can do a 1632 type thing…
Klingons, I CHOOSE YOU!
I summon the Tau Empire, for the greater good~!! :lol:
This is every bit as eclectic as I hoped, and more popular than I expected! I suppose this means that I’ll have to do actual work, now.
I know that I’m 3 months late, but just wanted to share a thought:
Quarians from Mass Effect.
Without their homeworld, flying around in a flotilla, struggling to survive and hoping that they will retake their planets once again.
Excellent scientists and engineers, but treated bad because of the stereotype of a Quarian petty thief.
Hell, because the flotilla has to fly as a one, and because of constant shortages of medicaments (and they need them because of the weak immunologic defense of the specie), food and weapons, and the need to sustain yourself on trade, admirals decide where shall they fly next, and what shall they do.
You could even place players as the Admirals, each with their own ship. It would NationShips. Whole concept could base on them.
But that’s just my fanboyism of them.
Your opponent’s weak GO Elysian Empire!
I’ll take the Weeping Angels. I hope your soliders have fun trying to avoid blinking!
— Begin quote from ____
I’ll take the Weeping Angels. I hope your soliders have fun trying to avoid blinking!
— End quote
Dibs on Time Lords 
They have a proven track record against your measly Weeping Angels.
Also, Jedi and Wookies/Ewoks dibs
— Begin quote from ____
— Begin quote from ____
I’ll take the Weeping Angels. I hope your soliders have fun trying to avoid blinking!
— End quote
Dibs on Time Lords They have a proven track record against your measly Weeping Angels.
Also, Jedi and Wookies/Ewoks dibs
— End quote
Jedi aren’t a species/nation, and the Doctor is a renegade Time Lord, y’see. The Gallifreyan authories think that they’re too cool to contact anyone else.
