Mature and Unique Shoujo Anime
Anime
Shoujo anime that may contain body horror, cosmic horror and various horror elements, serious topics such as rape and suicide. They might use different kind of storytellings most of other shoujo anime doesn't and more likely to have philosophy. Often well developed main characters, old and completed series.

TV, 2006,
39 eps
Me:-
Author:10
Slow paced because of the very detailed storytelling and a realistic story overall. It might not be an anime for everyone but it has very well written drama and is the best political drama I have seen till now. Main character is one of the best written protagonists you could see in media. Contains topics such as workplace harassment and gender roles. Also VERY feminist.

TV, 1999,
44 eps
Me:-
Author:10
A unique magical girl series focusing on the themes such as self isolation, depression and learning self love. Very well written main character, also one of the most badass ones you could see in shoujo anime.

TV, 2002,
52 eps
Me:-
Author:10
Same creator as Kaitou Jeanne and similar themes but it doesn't have action and focuses on drama more instead.

TV, 1992,
46 eps
Me:-
Author:10
The shoujo that arguably was the most influential after the well known "Versailles No Bara". Broke the limits of shoujo demographic such as first love stories, handled magical girl genre with a different perspective, mixed shoujo romance with various genres whilst showing shoujo doesn't have to be romance focused stories. The manga has a much more well written and mature story but episodic nature of 90s anime is a good set up for people who are getting into the series for the first time and want to warm up to the characters. Contains elements such as suicide, body horror, gender roles. There is some horror genre looking like enemies.

TV, 1995,
39 eps
Me:-
Author:10
Focus on the importance of "dreams" with a different take on topic in every episode. Has a more well written villain compared to previous reasons. Unique romance linked with the theme of dreams.

TV, 1996,
34 eps
Me:-
Author:10
Whilst it is much weaker than it's manga counterpart and has plot holes, the most serious and darkest season of 90s anime.

TV, 1995,
52 eps
Me:-
Author:9
Influenced by Sailor Moon and Marmalade Boy, Fushigi Yuugi had a slightly older target audience. Contains sensitive elements like self harm, suicide and rape.

ONA, 2014,
26 eps
Me:-
Author:10
Reboot that adapts the manga more faithfully and has a much more serious and darker atmosphere. It was marketed for adults. 90s anime is more urban fantasy due to it's episodic storytelling (although it still has more fantasy than most of non-magical girl shoujo) whereas Crystal, due to being faithful to manga is transcending the boundaries of imagination. Yes, I am talking about Sailor Moon Cosmos.

TV, 2017,
12 eps
Me:-
Author:8
A high fantasy shoujo, though I'd recommend seeing the manga more.

TV, 2007,
51 eps
Me:-
Author:10
Mahou shoujo series with magical boys getting same treatment as girls.

TV, 2003,
26 eps
Me:-
Author:8
Practically this is what magical girl genre with a male main character is, but of course it is more than that.

TV, 1967,
52 eps
Me:-
Author:-
From Osamu Tezuka, Princess Knight is the first female targeted series and focuses on gender roles.

TV, 1982,
34 eps
Me:-
Author:8
Romantic comedy packed with a lot of drama, Tokimeki Tonight is about the life of Etou Family where the mom is a werewolf and a vampire dad and their 2 children. One of the best selling shoujo manga.

TV, 2023,
24 eps
Me:-
Author:10
Shares many similarities with classic shoujo story wise. Uses anthropomorphism as a way to deliver it's message more clearly. Has a very well written cast including the villains (villains part is important because this is a problem I have realized in most of popular shoujo) I recommend seeing the manga too, since anime sadly had to skip some parts