From Tokyopop:

Confidential Confessions is a shocking new manga series that deals with many of the hard-hitting issues that teens face today. Using emotionally moving storylines and multi-dimensional characters, each groundbreaking volume tackles such topics as teen prostitution, rape, HIV, stalkers, suicide, and sexual harassment.

V.1 - Tobira (MOMOCHI Reiko)
1-3. The Door
4. Mistakes

V. 2 - Namida (MOMOCHI Reiko)
Tears

V.3 - Memai (MOMOCHI Reiko)
1. Our Future
2-3. Dizziness

V.4 - Itami
1. Pain
2. Distortion
3. Tomorrow
4. Forbidden Kiss

V.5 - Himitsu (MOMOCHI Reiko)


V. 6 - Uwasa

Series order as published by Konansha:
1: Itami (いたみ) (Pain)
2: Himitsu (ひみつ) (Secret)
3: Memai (めまい) (Vertigo)
4: Uwasa (うわさ) (Rumor)
5: Namida (なみだ) (Tears)
6: Tobira (とびら) (Door)

12 girls are imprisoned in a mysterious prison.

Fighting their way through this unjust and abnormal conditiions, these girls have begun a life and death struggle.

A harrowing little girl prison escape survival!!

Ichimatsu Kairo's ex-girlfriend, Kusakabe Hiyori, who disappeared 7 years ago appears before him again one day. As someone who was converted into a devout follower of the Hiyori religion, he became unable to live in reality when she left. Reunited, she divulges to him her unreasonable demand, "Ichimatsu-kun, I want my childbirth recorded so give me your sperm."

The inside of the taboo door is shattered, or...

The illusion of that person leads me astray. Mother and son. This is the ultimate favoritism.

From etc:
Bookish and naive, Angelo da Canossa is unprepared for life as a student in a university that hums with tension and intrigue in Renaissance Italy. Will his innocence remain intact when a chance encounter with the charismatic Cesare draws him ever deeper into the darker side of the Renaissance?

Note: In creating Cesare, Souryo has collaborated with a Dante scholar to bring to life a vivid portrait of Renaissance Italy in great and accurate detail.

Six months after the fight to the death with The Bog, Kaiji escapes from the underground and pays off his debts. Sakazaki gets fed up with Kaiji and tries to get rid of him by giving him 3 million yen as compensation. At that time, Kaiji is reunited with Miyoshi and Maeda, who were his friends in the underground, and they come up with a plan to swindle a large sum of money from Muraoka, the president of the underground casino where they work. Kaiji takes 3 million yen from Sakazaki, promising to pay it back, and plays a variant of mahjong called "17 Steps" invented by Muraoka.

Once, there lived a fearless girl who could defeat even the strongest of beasts with her bare hands. She was the strongest person living. Thousands of years later, the same girl from the stone age has lived to learn what romance is. Will her strength scare everyone away, or will it let her fall in love?

Take me to the end of the world... said Blaise Cendrars.
Come on, I'll take you, says Keiichi Koike.
He takes you on a trip through time and space to the end of the world that is also but the beginning of it all...

A story of a black cat who wants to taxidermy the head of a young girl.

Set one year before the main story and centred around Saotome Mary.

Saotome, a bright young girl born into an ordinary family, has passed her transfer examinations and started to attend Hyakkaou Private Academy. It's an elite school with a twist: gambling has become a central part of its academic activities. Saotome adapts quickly to this outlandish system, and will soon succumb to the gambling mania that she comes to be known for in Kakegurui.

Six old friends in their thirties meet at a gathering of former high school mates. Today, everyone has a stable life, but they feel dissatisfied. Because they left behind their childhood dreams, those they would like to find back...

On that day, suddenly, every single male virgin over the age of 18 started dying rapidly, causing a huge panic across Japan! Sex industry prices skyrocket overnight, forming angry mobs of terrified virgins, and the government knows not how to handle such an unprecedented crisis.

Enter our protagonist, 17-year old virgin Kurumi Eiri. He has to get laid before his 18th birthday, or he'll die! He hurriedly confesses to girls, only to be shot down without any hope. Is there any way for him to graduate from virginity?! What will the virgins do when death is staring them in the face?!

The struggle for survival between humanity and Parasites continues unceasingly around the world. Unfolding in the shadow of the legends of Shinichi and Migi, another battle for existence is revealed. Fukami, a veteran detective, investigates a brutal mass murder, and is unsettled by the composure of the informant: high school student Tatsuki. The source of that discomfort lies within Tatsuki's family...
The tale on the other side of the ageless masterpiece "Parasyte" begins here!

Kaguya Hinaki is a female college student who is highly regarded by her classmates because of her good looks. She had a secret she couldn't tell anyone, the secret being that she is genuinely in love with Subaru, a member of a certain streamer group.... Hinaki, who really wants to go out with Subaru, receives a DM from a strange account one day, and Hinaki's life changes completely――。

A world where wars are fought with spies. With a mission success rate of 100%, the remarkable, yet rather difficult to deal with, spy Klaus is being tasked with an almost impossible mission by the agency, harboring an insane 90% chance of failure and death…which for some reason involves eight inexperienced girls?!

We trust professionals with our money, our possessions, our health...even the future our children. You could say such individuals deserve to be called "professionals" because they act in a way that merits such a high level of confidence and faith. However, there's a sacred ground that most people are loath to let even the most consummate professional trespass into: the mind. Is it possible - or safe - to let another human being psychoanalyse you completely? Who can guarantee that the experience won't irreversibly change you...for the better or the worse?

This is the story of a genius psychologist, Dr. Frost, who's capable of just such a deep level of psychoanalysis.

Amagoe Homura, a high school student you can find anywhere, finds himself in a devastated version of Shibuya. A mysterious figure calling himself "Unknown" tells everyone that they can commit any crime in this world, and forces them to participate in a death game where they compete on who can commit the most severe crime...!

From the author of “Sensei’s White Lie” comes a new, shocking piece.
Kaji Ritsuko, an author of short stories, finds herself unable to write. On a certain day, a remnant from Ritsuko’s past reemerges. Aoi, a male friend she used to completely confide in, appears in a dream and asks her, “Your life… is that really it?”. The next morning, Ritsuko is awakened by a phone call. Aoi has committed suicide. The glimmer of a forgotten dream, the day-to-day of a modern couple, the death of someone irreplaceable…
A life of “loss” that she had always averted her eyes from begins to move…

Alice Fujii still isn't having much fun. She survived an assault of psychotic bug-themed assassins at her school, but all the battles, the truth behind her family, the two betrayals from false friends who ended up dead and the loss of her Kumoito knife-gun took a toll on her mental state. As such, she spends her days alone splitting open the heads of the rapist zombies who overran Japan since the aforementioned incident. The Organization wants to hire her as their new Boss, and elsewhere her allies Gokiburi and Kabutomushi are looking for her. What will become of all this?