When I created Cassandre, it was supposed to be a male. I drew it as a male, and then, when adding the text parts on its reference, I changed my mind and wrote "female". Making Cassandre a female.... but only from a biological point of view.
I'm trying to make her as ambiguous as possible : she is neither masculine nor feminine, she doesn't identify as male nor female, I like her to be very androgynous. Her pronouns are interchangeable too, I sometimes use "him" to mention her.
Beside this, not sure if it counts, but I have genderless characters (they have no genital organs and no societal need to identify has a gender, then they just have no gender at all). Some might have a more masculine body has they have pec muscles (that they need) instead of breasts (that they wouldn't need) but they are meant to look androgyne. They're neither masculine nor feminine.
Osiu - Anok - Diey - Galico
They're all anthros though, then maybe they aren't what you're looking for.