I read a whole article about this and yet I still came here unsure of what term I'm supposed to use (lol), but I'm looking for recommendations for novels involving F/F romance, without that meaning that the primary genre has to be romance though. I'm curious about adventure (in either a fantasy or realistic setting) and sci-fi stories, but historical drama or slice-of-life would also be good. I don't really mind the age of the characters, but I don't want an age gap romance. Incest is also out (note: step-sisters who haven't grown up together are okay). Oh, and no vampires/werewolves please. NSFW scenes are okay, but not as the main focus.
I'd rather it be available online ('cause I can't afford to have them in my library for a number of reasons...), so webnovels and amateur original works are more than welcome, as long as they are completed.
As for what to call it, there's a lot of answers and it usually depends on where it is from. Western fan fiction and amateur works often use F/F, femslash, or WLW. Western published novels tend to be under Lesbian Fiction (shortened to Lesfic by fans), though the Girls' Love (GL) term is finally gaining some ground outside amateur circles, especially on online platforms. Manga, manhua, and manhwa usually use Yuri (which you probably already know).
I've read a good 400 or so Lesfic novels in the past 5 years, more if we count amateur works. Personally, I tend to avoid fantasy and sci-fi settings in general because most of the Lesfic novels I've read in those subgenres are not particularly great. It seems like the genre isn't mature enough in this particular area, and even some of the mildly popular stuff feels like self-insert power fantasy, which can really take me out of things. That said, it's obviously not all bad (nor is this problem endemic to Lesfic, see popular mainstream titles like Ready Player One for non-GL examples).
Anyway, here's a few of my favorites that fit your requirements, spread out among different themes:
* The Lily and The Crown - One of my favorite Lesfic stories of all time, and it is even Sci-Fi. It manages to capture some really unique emotional spaces and situations, and it comes up in my thoughts periodically even years after reading it. There is a bit of age gap between the characters but... it isn't ever really relevant, and the younger lead is still in her 20s.
* Poppy Jenkins - Nice little romance novel about a quiet Welsh town.
* Chasing Stars - Superhero romance. Good change of pace.
* Gideon The Ninth - This is the least romance-focused suggestion, but it is so unique and interesting I would have considered reading it even if there wasn't any romance at all.
* About That Kiss - One of many Hollywood/actress-focused romance novels. This is my personal favorite of that setting.
* Tryst Six Venom - This is a really weird one because the leads start off hating each other so strongly. I almost stopped reading about a quarter of the way in, but it actually kind of became an odd favorite.
Also after typing up this post, I remembered there is a dedicated thread here for Lesbian Fiction in other media, which probably has a lot more book suggestions, though I do remember that it focused a lot on movies and TV shows.