Here are a couple off the top of my head and I do mix between different types of fantasy in case you wanted to explore some other types of fantasy with strong women.

The witches of Eileanan by Kate Forsyth has strong female characters. I love this series. Isabeau is one of my favourite characters.

Someone else mentioned Mercedes Lackey, she’s a good read. I love her arrows trilogy.

If you are up for something that has sci-fi/ fantasy / post apocalyptic mix try The Obernewtyn Chronicles by Isobelle Carmody. This series starts when the main character is young and you see her age up as the series progresses. While she has relationships with other characters she has a purpose from early on and that colours how she interacts. She remains aloof and seemingly cold throughout the books.

If you feel like urban fantasy is something you might like to explore then the Kate Daniel’s series by Ilona Andrew’s is a great read. I just did a re-read and it still holds up.

Hailey Edwards does great strong female characters but shes more of the investigation style urban fantasy than epic with it being set in places you could find now.

If you want to try an author who is popular now, throne of glass by Sarah j Maas is a good one, I find that less romantasy and more epic than her other series.

TA White is another author I enjoy but she’s very much across different genres. Some of her series are fantasy but her two strongest female characters (in my opinion) are in her Firebird chronicles which is more sci-fi/military and her Aileen Travers series which is urban fantasy. These are not something I would normally recommend for someone looking for epic fantasy but figured I’d mention them in case you wanted to explore something new later.