Most of who I've had in memes are TTRPG OCs Bel (who is also my BG3 Tav) and Ilphyl, who are brothers. Also AMAB drow raised in the Lolthite religion, so I need a CW for abusive relationships.
(Ilphyl is non-binary, but will always use 'son'/'brother'/etc. when describing their relationship to their biological family, because they have trouble seeing words like brother/sister/sibling as meaning the same thing beyond 'gender of person'.)
Bel wasn't close to his mother; which was probably for the best, as I think he assumes she thinks he's a generally disappointing child. Ilphyl was the one who has the complicated 'I recognize I'm never going to get what I want or need from my mother, and she assumes I'm dead, but that doesn't stop the emotional reaction'.
Tabletop wise, I have a goron (who I tend to assume are a single-sex species) and a robot, and two characters whose families I haven't really thought much about.
For fandom... Zelgadis's bio parents are dead, and when he was young enough he has no memories of them. He didn't really have a maternal figure growing up.
I've been playing Simon in memes, and he had two mothers (and a father -- his parents were poly). It's mentioned that the thing that strained the relationship with his twin was Sylvester wanting to pretend their non-biological mother was their mother, because it hid the fact they were born half-human, and changed to be fully fae.
(Also been trying out Aerich, who has zero mention of his mother in canon. We can assume his parents had an arranged marriage, and it's possible that after his father died in disgrace, she went off to do something else, but it's entirely headcanon.)
I don't think I currently have any characters who are mothers who I'm actively playing. I should try that.
(Another thought; realizing that Ilphyl's mentor became a mother-figure to them, to the point where her extended family is all 'yeah, that's Yebe's kid. What? Oh, yeah, they are a drow. She adopted him'. Picture a sprawling clan of forest gnomes deciding this one drow adolescent two of them brought back from the Underdark is now Family.)
(Ilphyl took a lot longer to figure out that that was what happened.)