Were these groups generally polyamorous or monogamous? Were there prohibited sexual acts or specific religious or legal practices forbidding or encouraging masturbation or homosexuality and homosexual conduct?
If you don't get a response here, you might have better luck cross-posting to /r/AskAnthropology
No society has been proven unambiguously matriarchal, but I was primarily thinking about ancient Crete and Germania. The question could also apply to certain native American tribes such as the Hopi which are more egalitarian. I do understand, given a limited sample size, how this question could be challenging to answer and probably why I haven't been able to find any information on it.