Ohh this is a great list! I've been eyeing both The Summer Hikaru Died and Our Dreams at Dusk for a while, I should really make time for them this summer 🙂‍↕️. I also agree with your inclusion of Witch Hat Atelier, I feel like Shirahama has managed to create a story that can fit for any audience above 10ish yo, which is truly a tour de force. In case you are looking for recs, both for the list and in general, I feel like My Broken Mariko by Waka Hirako could fit in great. It is a one shot following a young woman trying to process the death of her best friend. It has a long list of trigger warning as it deals mainly with suicide and the consequences of abuse, but it's a manga that really touched me. Its drawings are almost haunting and I felt so deeply for the main characters! As far as I know, it was serialized in Josei web magazines before being published.

At original time of posting this list is my own personal recs, and bestselling/well-known influential titles. I have excluded a few bestselling titles that I felt would not necessarily feel "mature" to newer manga readers in 2026, like Oh My Goddess! and Crayon Shin-Chan. The former in particular, imo, is actually much tamer than a lot of shounen titles of today, though the protagonist is a college student who drinks and rides a motorcycle. A large portion of bestselling seinen titles are humor, ecchi, sports, and crime dramas - most of that have not seen official English translations. Also posing a problem are several titles that started out in one demographic but moved into different magazines - see Captain Tsubasa and Fushigi Yuugi, which made similar leaps from being shounen > seinen and shoujo > josei. Then, as if to give me a headache specifically, one of my favorite series, Saiyuki, has run in shounen, shoujo, and josei magazines. It's been running since the nineties and tastes have changed a lot. Men like the violence, women like the hot guys, who the hell knows. (/s) I may take these kind of series on a case-by-case basis.

Kamome Shirahama of Witch Hat Atelier has apparently said she hopes that women and young girls will enjoy her work, but it does run in a seinen magazine and as the story goes on it does get darker as well as touch on mature subjects that are given in-text trigger warnings.