[ Just some silliness below...]
So in my current game as a Benevolent Superpower (Mega-Evil *off*, but I'm generally exercising restraint, and am subsidizing client states. Victory conditions set to something like 2 years of peace.), other known non-neutral races are the Ukra-Tal, the Klingons, the Jraenor, the Segretti, and the Phong.
The Uktra-Tal and the Phong are my allies -- both Brotherly, both periodically asking for full partnerships (which I'm loathe to accept, because when they see my full holdings the jealousy factor may skyrocket) and both, to my annoyance, nominally at war with each other. The Uktra-Tal in particular have benefited quite a bit from considerable gifts in technology and resources from my peace-loving, kind-hearted, and incredibly heavily-armed people.
The Klingons are subjugated; they used to drop by my space every once in a while until I ordered the construction of mines and minelayers and hired a minister to handle such their use... but, for now, they appear to be under control.
The Jraenor are allies, but rather angry ones. Aside from their quarrel with the very recently subjugated Klingons, they appear to be quite calm. Oh, and several of their warships are on an extended tour throughout my space, escorted by volunteers from my own navy who can show 'em around.
That leaves the xenophobic Segretti, who have repeatedly tried to attack my outlying worlds -- while they still had a fleet; it appears that they may not have a fleet anymore, as my spies now report failure when trying to convince crews to defect, whereas once they were reliable... It's basically an undeclared war exacerbated by their stubborness.
But in any event, through no particular fault of my own *cough* a Segretti world that appeared to be well-positioned as a staging base for them had its government overthrown, after numerous attempts and a strange amount of message traffic from my worlds *cough*...
But it promptly declared its independence and cheerfully ignored my heavily-armed fleet that was, er, just protecting a formerly Segretti construction base that had for some inexplicable reason joined me, and just might have been ever-so-irritatingly-slowly working on an Invader-class ground-assault battleship.
The message traffic continues, and the new faction proves highly unstable, as yet another revolt occurs on that world... and forms ANOTHER faction, which again asserts its independence and continues the obnoxious Segretti tradition of insulting my people.
Then due to a most unfortunate accident, an order must have been mistakenly sent which resulted in the colony being annihilated. Must have been some bit flips in the message traffic, I'm afraid. Hopefully the next Segretti colony to be visited will avail itself of my protection.
-- The thing that goes bump in the night