I haven't come across any yet....but there was that one manga? Or was it a webtoon? Where the parents of the mc was a female alpha and male omega....
Here both female https://nhentai.net/g/259049/
http://www.mangago.zone/read-manga/hebi_no_seikatsu/ - Ch.1-3 Their Parents are both woman
Actually in omegaverse au (if I'm not mistaken) female have dicks as well instead of the clitoris, or at least that's something I read somewhere
Is there a story wherein the lead roles are a woman who's an alpha and a man who's an omega??