Xenophile:
Gardeners of Diversity: Busy sitting creating new life and genetically designing servants and friends. Really don't want people to go around teching AI too aggressively, nor any enroachment of borders. They are willing to trade, especially with other xenophiles.
Xenophobe:
Bastion of Purity: They are convinced any other specie is unclean and potentially dangerous to even go near. As such they will destroy any ship going near their border and declare war to remove any colony near them, never going a certain distance from their border, afraid they might become tainted. Good luck with diplomacy.
Pacifist:
Upholders of the Compact: 15000 years ago the galaxy lived in peace, and all nations signed a galaxy wide contract stipulating a few things. Such as never more than 15 battleships, no anti-planet weapons, no settling planet Ixail, etc. Most signatories are long gone, but not this FE. They remind all the young races the treaty still holds by saying "You have too many battleships according to clause 15.e-1456. We are required to inform you that you have 1 month to correct this. Have a good day." Perfectly reasonable and amicable with no intent of warring, and they are so sorry they have to enforce the compact. Always willing to do diplomacy but only for short durations as they don't entirely trust new nations who werent there.
Militaristic:
Paranoid Defenders: They are sure other dimensional threats can come at any moment, just like they did so long ago. They are also sure that any citizen or independent thought might be indicative of infiltrators. They sit and build ships at the same rate they purge ships for suspected infiltration. The more you interact with them the more they are convinced you are out to get them. You just look weak because that is how "the others" want you to look.
Intergalactic Vanguard: A forward force sent by a distant empire through a supergate. Supergate broke down and now they are stranded in this galaxy. Their directive is to establish a beachhead, and they have done exactly that. So now they are a hyperadvanced force without any instructions, and really don't want to do anything on their own initiative as it violates their military doctrine. They should have the scariest fleet by far but be smaller in size. Anyone who starts to come near them in terms of military power might have to be preemptively attacked to secure the beachhead, and woe to the one who goes aggressive expansion near them.
Collectivist:
Unity Eternal: They are convinced they have achieved perfection. They have an optimal amount of everything, and want for nothing, expansion will just risk losing the perfection they have obtained. They do not even accept gifts as it is needless. They will also be the hardest to provoke into conflict, but really dont want you doing anything inside their borders or pushing their borders back as you would be disturbing their perfect borders.
All as One: They have basically removed free will and sort of exist in semi-conscious stupor. Think of a hive mind that really really botched it. It might be starting to lose it. Might have -75% productivity -100% ethos divergence. It turns out that free will might be useful for something and it is starting to feel more and more jealous at other younger nations who have it. Might attack some to get at their free will deposits, especially if they are good at teching, because it really would like to remember how to do that.
Individualist:
Anarchist Federation: The government has basically fallen, some pun intended, and all that is left are a few particularists just going about their daily lives. Which is nothing in particular. Their leader is powerless and can not even perform diplomacy legitimately, so good luck with that. They have far more fleets than other FE but each is smaller, as people don't trust each other with military power. It is more an empire in name than in practice. Though if anyone threatens or provokes them, you will find a very resilient enemy. They really really don't like the idea of a space emperor or any dictatorship gaining too much land.