Chiko is a high school student who can see other people’s red threads, which is the thread that connects one person to his/her soul mate. She uses her ability as a musubi-ya to advise her schoolmates on their love lives, for a fee of course! But upon stumbling upon a hidden room at her school, she sees a mysterious looking white spool of thread that suddenly comes alive and traps her. The next thing she knows, her body has become like a ten-year old kid again and the only way to get back her body is to use the mysterious thread to expel evil spirits and become a real musubi-ya!

Alice Ryouhei will leave high school soon, but he's trying to avoid thinking about his future. Late one night, when he's hanging out with his tough friend Karube and his silly, girl-crazy friend Chota, they see fireworks. After one blindingly bright explosion, they find themselves waking up in a different world. In this 'Borderland,' people are forced to either participate in potentially deadly games or simply die. Will Chota, Karube, and Ryouhei be able to survive this dangerous new world, and is there a way they can get back to their original lives?

Fujisawa Ayana was horribly bullied at school. At first, she tried to defend herself, but she soon learned to just stay quiet and wait for the pain to end. However, the bullying escalated one day, when someone pushed her into traffic. At the hospital, as she recovered, she suddenly realized that even if she didn't fight back, her classmates were probably going to eventually kill her.

From this realization, she soon decided that the only path left was for her to take revenge. Her new plan included the students who bullied her, those who stood aside and laughed, and those who did nothing to make it stop. She began gathering notes on her classmates, planning exactly what she could do to make each of their lives collapse. While some of the students really seemed to deserve their fate, her plan also included classmates that she used to count as close friends...

From Aerandria:

Mermaid is a beautiful blind girl from a very wealthy family who has constantly been sought after by rich gentlemen who covet both her wealth and beauty. To finally make them stop, she agreed to marry the one who can make her hear something amazing and unheard of before. As each gentleman fail one by one, one particular man of common origins resolves to make her wish come true. See to what lengths love will go for the heart’s wish…

From Here:
First year high school student Karin holds tightly to the memory of her childhood love Yuuki-kun; so tightly that she still wears her hair in the same childhood style (two ponytails) to be sure that if they ever meet again, he'll recognize her. Delivering papers to the school infirmary, she meets up with a boy who seems to be coughing up blood (of course it's actually juice). He's an incorrigible prankster who can't resist teasing Karin constantly and pursues her even after she tells him she's still loyal to her first love, much to her consternation!

A spin-off of the main series focusing on the white rabbit, Peter.

A chance for an interview for a large company is given to a man who has nothing to show for himself. An authentic fiery interview will now begin! Are you paying attention? Get ready!’ Lee Hyunmin’s <Hear My Voice> begins!

From Tarot Cafe:

"Why is my life so messed up?!"

Haeun has a step brother who's a gang leader and she gets blamed for everything he does. When her brother makes it so that she is late for class, she has a strange encounter- the encounter that makes her a housemaid for the rest of the year. Haeun, who hasn't even had her first kiss yet, decides to take revenge. But when she finally kisses someone -and it isn't pleasant- what will happen?

Kaori Fujimiya is always alone because all of her happy memories, including time spent with her friends, disappear every Monday. Deciding that he wants to be friends with her anyway, Yuuki Hase tries to get close to Kaori each week, wishing that she would one day call him “a friend”.

The world is split into two kinds of people: those on the "inside" of EDEN, and those on the "outside". Within EDEN there is clean air and water - it lived up to it's name of a true paradise. But EDEN cannot contain all of the people of the world. EDEN actually made conditions worse for those outside. Because of this, many resistance groups have been formed. Ricalna Forde is a soldier of the resistance team COSMOS, whose mission is to infiltrate EDEN's main headquarters and destroy the "Central CPU" - that controls all of EDEN.

From ShoujoMagic:

1-2. Andalusia no Koibito
Hikaru was engaged to a man who had a great personality, a handsome face, and an annual income of ten million yen. Anyone would've envied her. So who is this new man she wants so badly that she ditched her fiancé? "Andalusian Lover" is an inconceivable tale of love revolving around the ultimate greedy woman!

3. Love Fool
Saeki Noa met a girl on a boring group date. Noa is a hot hunk but this girl after their first date thinks he is a jerk and wants to make him fall for her and dump him...but...

4. The Boy Is Mine

A spiral love story. Kouno Jun is a lively character who lives life with all his might. In kindergarten, he falls in love with Hasebe Rino, the most beautiful girl in his class, and he confesses to her. Hasebe accepts his love, but the moment she gives her answer, she vanishes on the spot. Failing to figure out what's going on, Kouno asks his friends about Hasebe, only to find out that no one remembers a single thing about her. She has just vanished, along with all memories about her, except for those of Kouno.
While Kouno leads a weary and desperate high-school life, Hasebe appears again as a transfer student. However, this Hasebe is not exactly the Hasebe he knows.

Tanaka Manabu is a geeky student. One day on the way to school he meets a girl carrying a bloody bat. That girl is Ryuuzaki Reina, leader of the school's female delinquents. It's love at first sight. A gag manga (with a combination of 4-koma and normal page) about having a yankee dere-dere girlfriend.

Note: In the title of this series, "yandere" isn't referring to this term, but instead it combines "yankee" + "dere-dere".

Yandere Kanojo comes out in two editions. One is the "magazine version", Yandere Kanojo (Joker); and the other one is the "online version", Yandere Kanojo (Online). Both stories follow the same storyline, characters, and concepts; however, each version shows different events while not contradicting the other.

A European mystery romance, "Glass Shoes" - the long-awaited conclusion!! The clever Bild, who has figured out that it's Al's spirit currently inside Saylie's body, begins a plot to get rid of Saylie, who will become an obvious obstacle in the future... Meanwhile, Debroyl asks for Saylie's hand in marriage, claiming that he loves her just the way she is, however...?!

Pu Reum Han led a normal high school life, that is until, he dreams of a lady, looking for his help to find her missing baby. But what if that baby is inside him?

Have you ever wondered why Koreans ask you about your blood type? It’s not because they want to know what to do in case you happen to be in an accident (although it really is vital information), but it’s because there is a underlying belief that blood types affect personalities and character in the way an astrological sign may.

Another hugely successful webtoon, it has packed all the existing stereotypes of each blood type and more into a hilarious series. Strangely enough, there are many which are so darn true it’s kind of uncanny. Much funnier when you know your own blood type.

Ichinose is a boy who all his life he was bullied, he has this ability to see ghosts and one day he meets a dog that is trying to tell him something, One day he meets Shiranui, Senka, who is a Ghost Child, a child who can see ghosts and fight them to purify them. Ichinose decides to help Shiranui out to fulfill her wish.

A boy wakes up in a strange room and finds a girl passed out with him. They find out they both have weird collars on. The boy has a phone which seems to be connected to the people behind this. They want them to do what?

From MangaHelpers:

There are huge monsters wreaking havoc in Mikagura Kiriwo's city. Building on his father's work, Kiriwo has created a serum that turns him into a giant monster for a short time. He uses this serum to help protect the town from a monster one day--only to find that everyone thinks he's an enemy, too! Everyone at school and in the media hates the "black monster" that he became, due to the massive destruction he did to the town around him. A girl from his class even has to quit school, due to problems caused by the "black monster." Will Kiriwo be able to show that his monster form is really intended to be a savior? [tethysdust]

The world is in a state of isolation. The cause is due to mysterious deep sea entities the navy has dubbed the "Deep Sea Fleet" and they're taking over the seas, isolating all the countries of the world from one another. Refusing to just sit idly by and let the Deep Sea Fleet have its way, all the countries of the world pool their resources to make a new weapon to combat them... a weapon that is comparable in power to that of a battleship... and its name is: The Fleet Girls. Will this new weapon be enough to combat the Deep Sea Fleet? Will the ensign that was just sent to the naval base where the "Fleet Girls" are kept be able to aid in their struggle... Only time will tell as this war against the Deep Sea Fleet begins to unfold.