Biologically, I consider Pyronites agender at default (inevitably by process of space travel and meeting cultures in which gender is prevalent there will be Pyros who think social gender sounds awesome actually and promptly trans their gender), we’ve only seen Pryonite transformations and hybrids as full characters, leaving them up for interpretation in my opinion. Any two of the species can mate, in which they will mutually erupt in flame until a rocky body is formed from their combined material and a fire inhabits it.

(Which results in a very interesting kink scene for other species with a thing for burning)

Vulpimancers lack a social concept of romance. Which in a way means they have an aromantic society but also not because they have no reference of what romance is to consider themselves devoid of it.

Necrofriggians are an agender and sexless species we all know this.

Anur Transyl has a very prominent queer scene, it effectively goes hand in hand with accepting so many different cultures as a multi species planet.

On that note, Ectonurites are a sexless species that reproduces via apomixis. Though they do have a cultural understanding of gender that translates to our understanding of m/f, but it has nothing to do with anything related to reproduction.

Tetramand culture has a very prominent f/f culture in its history. Many of female Tetramand that were unable to be defeated by any man were instead eventually bested by a woman and were promptly betrothed. These pairs were typically renowned as images of strength. M/m couples took longer to be accepted, unfortunately, initially being regarded as both partners being too weak to court a female.

Polymorphs are biologically sexless and socially genderless. Single cell organisms don’t have much to work with.

Lepidopterrians are a tri-sex species. Sexualities are thought us which of those the individual is attracted to. Three for exclusive attraction to each one, three for any combination of two of them, and one for attraction to all and any. Which of the three the individual happens to be is not considered.

Piscciss Volanns have the natural ability to change their sex when their current environment necessitates. Now however, it is used also as a way to transition for bodily dysmorphic transgender Volanns. Due to the larger size and different physicality of the females compared to the males, it’s a long and rather strenuous process, but is met with much celebration when completed.

Planchaküle treat genderfluidity as the default. They love their adaptations after all. Can’t leave one thing as it is for too long.

Methanosians have four sexes. Two which produce pollen, pollination functions with only one of them providing the pollen, but the two of them joining together in the act results in more diverse offspring and is the social norm. The other two are the pollinated. The first of them will always bare offspring of the two pollinator sexes, while the other will always bare offspring of the pollenated sexes. Perhaps not the most streamlined reproduction cycle but it seems to be working for them.

Cerebroian Currmary all default to male as a result of their biological programming. This was unintentional of the Cerebrocrustians, but they would claim otherwise. Many decide they prefer to be female, neither, or both however.

Galvanic Mechamorphs don’t have sex, but they do base their gender off of the Galvan’s because they think it’s neat.