Films that are about friendships between women, not films that feature one as a subplot. e.g. films that are structured around the arc of a friendship, or where that's the central relationship in the film.
I'm also thinking more about friendships between women of a similar age, rather than intergenerational friendships where there's a sort of surrogate parental dynamic... although that's not necessarily a hard and fast rule! e.g. Clouds of Sils Maria is about an intergenerational friendship, but there's nothing parental in nature about it.
Also trying to steer away from films about sisters, because I think that's a different kind of relationship entirely and deserves its own list!
This is for research, sort of, but also just because I like these kinds of movies.