Aimtroogs
-Homeworl: Kujja.
-Group: Reptilia (humanoid subgroup)
-Average height, weight and lifespan: 9 feet, 150 pounds, up to 200 years.
-Species traits: intelligent, but physically weak due to having evolved in a low-gravity environment. Thanks to their education, many are natural engineers.
-Home system government: Aimtroog Consensus (rational consensus).
-Total opulation: 25 billion.
-Racial slur: longnecks, noseless, Greys.
The aimtroogs are the technological powerhouse of the Confederation, being the core species that supplies the highest number of scientists, and were the ones who made the critical discovery of Hyperspace. They're quite weak despite having an average height of 9 feet due to the low gravity of Kujja; despite this, many aimtroogs are quite willing to perform violent works, serving in the military or turning to crime.

Älfs
-Homeworld: Altea.
-Group: Mammalia (humanoid subgroup).
-Average height, weight and lifespan: 5.5 feet, 140 pounds, up to 1000 years.
-Home system government: Älf Kingdom (irenic monarchy).
-Species traits: all are psionics, and quite charismatic, plus very longlived, but their population growth is stagnant except for baby booms and don't adapt well to non-confederate environments.
-Total population: 30 billion.
-Racial slurs: pixies, elfs, leaf lovers.
The älf species (they call themselves alteans, but nowadays that only applies to those from Altea) is the main contributor in psionic teachings and the mainstay of Psionic regiments due to all of them being psionics. Despite their nearly-human appearance (the only differences are their lighter frames, hair color and pointed ears) and capacity to interbreeding, humans and älfs are not related at all. Due to the Hoxxes Incident, many älfs and darfs are at odds with each other despite the closeness of their governments. Despite them simply being respectful to nature, many species, darfs included, think of them as nature-obsessed weirdos.

Darfs (sometimes called dwarves)
-Homeworld: Gardelgard.
-Group: Mammalia (humanoid subroup).
-Average height, weight and lifespan: 4.5 feet, 150 pounds, up to 300 years.
-Home system government: Darf Systems (communal parity).
-Species traits: darfs are generally of tough bodies and very industrious, but in contrast to älfs they aren't very charismatic, and theirs is the species that hates Hegemony species the most after the therawyrms; it may not seem a problem, but that means that ships with darf captains cannont be place in borders shared with the Hegemony lest they restart the war.
-Racial slurs: groundlings, walking beards, stunts. Despite most darfs not minding being called it (and many actually liking being called that), 'dwarf' is nowadays associated with people diagnosed with dwarfism and therefore is considered a slur by many non-darfs.
Darfs are considered by many to be the the anthitesis of älfs: where an älf would speak or hide, a darf would attack; whereas älfs are all psionics, darfs psionics are extremely rare; and while älfs have some differences with humans, darfs might be a human subspecies (their beard-related cultures is simply a case of extreme machism, not a racial trait). As mentioned above, many darfs think of älfs as traitors due to the Hoxxes Incident in which several thousand darf colonist were left to die by an älf captain.

Gazam
-Homeworld: Shanrak.
-Group: Mammalia.
-Average height, weight and lifespan: 6.2 feet, 160 pounds, up to 150 years.
-Home system government: Gazam Sorek (representative democracy)
-Total population: 50 billion.
-Species traits: gazam population is always growing (it was 120 billion before the Hegemony War), but the only species that don't find their appearance and customs disgusting, freaky or otherwise alien (or edible for that matter) are humans, darfs, katdir and therawyrms.
-Racial slurs: pork, piggies, swine-things, hogs, fossiles, antiques.
-The gazam, alongside the the humans, are THE Core members of the Confederation, having formed it in the galactic year of 2472 when both fledging empires were threatened by Marauders, and when they finally won the war, rather than going their separated ways the gazam and humans decided that there was safety and strength in numbers. Nowadays both species are so close and so similar that the only real difference between them is that gazam are suids and humans are apes.

Humans
-Homeworld: Terra.
-Group: Mammalia (humanoid subgroup).
-Average height, weight and lifespan: 6 feet, 150 pounds, up to 160 years.
-Home system government: Terran Union (direct democracy).
-Total population: 50 billion.
-Species traits: humans are an adaptative species, and while not the most populous they are the most widespread species across confederate space, but it takes longer for them than other species to learn their mistakes, since Terra suffered a global nuclear winter three times in just one century, the last one AFTER they founded the Confederation.
-Racial slurs: apes (shared with mammalian humanoids), Morties, fossiles, antiques (oldest core species alongside the gazams, which share slurs).
-The species with the third largest population, the Terran Union was the co-founder and initial Core member of the Confederation alongside the Gazam Sorek, united in a common cause against a Marauder fleet that threatened the territories of both. The most remarkable thing about them -aside from being the cofounders of the Confederation- is that despite their relatively average lifespan they're the amongst the oldest civilizations in the Milky Way still standing, having discovered the Warp Drive in 2200.

Kadren Cabal
-The Kadren Cabal is not a government per se, but a smaller alliance founded between the birth of the Confederation and the outbreak of Hegemony war by smaller factions, and many non-Core members of the Confederation protest at the fact they have a senator, even though the Cabal is pivotal enough to having earned its place in the Federal Senate.

Another interlude, this one about the Core members of the Confederation. Well, the first half at least. The älfs are literally the Alteans from Voltron because I like the show, but the commie dwarves is exactly what happened to me in my game.