To be fair, we might see some of these adapted soon.
Weekly Shounen Jump is a manga magazine known for legendary manga like One Piece, Hunter x Hunter — or, recently, Jujutsu Kaisen and Demon Slayer (Kimetsu no Yaiba).
Adaptations of WSJ manga tend to do quite well — despite that, some popular series from it still haven't received an anime.
Sakamoto Days
Probably the most popular Shounen Jump manga that still doesn't have an adaptation announced or released (although rumors pop up occasionally), Sakamoto Days follows the life of an average convenience store worker, Tarou Sakamoto.
Or, well, he tries to be a normal person, but his past as a legendary hitman comes back to him every now and then. The series is mostly focused on comedy, though there's plenty of action.
Kagurabachi
A manga that's already known for one of the most vocal fanbases online, Kagurabachi is loved by most who read it. It's been basically accepted that it will eventually get an adaptation, and the only reason why it hasn't happened yet is it not having enough chapters.
The premise is pretty simple — a son of a swordsmith coming to take revenge on his father's killers — but it's the execution that matters, and the sword fights are absolutely epic.
Akane-banashi
While the classical Japanese art of rakugo was considered to be exclusively for men throughout most of history, that isn't the case now. This is reflected in Akane-banashi, where the protagonist, Akane, wants to get into the art.
Her motivation is actually unusual: she's inspired by her father, and she was heartbroken when she learned that he didn't get accepted by an older performer and gave up on the art entirely. Now, she wants to take revenge on the man who denied her father before.
Witch Watch
A manga by the creator of Astra Lost in Space (Kanata no Astra) and SKET Dance, it was obvious from the very beginning that Witch Watch was going to be very popular.
The manga is mostly a supernatural comedy following Nico, a new witch, and Morihito, her childhood friend/crush/familiar. It's not just about romance, though: the two end up being involved in all kinds of supernatural hijinks.
Ruri Dragon
One day, an absolutely normal high schooler Ruri Aoki wakes up and finds horns on her head. Yes, she's apparently half-dragon — her mother knew it all along. Ruri is not very fine with it, though. After all, dragons are very different from humans, and her life is about to experience some crazy changes.