1-3) Bunbetsu to Takan
Aya has a great boyfriend Kento who treasures her a lot. But she is also attracted to Kento's older brother, who has a twisted personality. How come she can't stay away from him and she goes so far to cheat on her boyfriend? Will Aya's sense prevails over her sensibility?
From Jshoujo

2) Delusional Diary
Ui fell in love with the wrong guy. Jiro is popular and handsome, and agreed to date her, but he insists that their relationship should remain a secret. Ui starts to feel more uncomfortable about her love situation and her trust in Jiro is weakened by his cold attitude towards her. Is Jiro cheating on her or does he just have a very weird way of expressing his love?
From Evil Flowers

3) The Little Mermaid who Became a Witch
Everyone knows the story of the little mermaid who fell in love with the prince and exchanged her voice for a pair of feet. Did anyone wonder about the witch’s story and why was she so bitter towards the young mermaid? An interesting twist of the classic “The little mermaid”, this time, from the witch’s point of view.
From Evil Flowers

from -dokidoki- :
Ichirou's best friend Naoto's noticed that he's been acting a bit unusual since summer vacation. With a bit of best-friend solidarity, Naoto squeezes out the tale of Ichirou's secret summer fling: a sexual encounter with a mysterious stranger fleeing from a rainstorm. Naoto is, naturally, scandalized, but not half as scandalized when he and Ichirou run into the summer fling again at a school festival...

As if a guy falling in love with another guy wasn't complicated enough! How about when that boy's already got another guy after him? Throw a live-in cousin with an aggressive crush and the world's cutest lovestruck best friend into the mix and the situation gets rather convoluted, even by Koide-standards.

From Fantasyshrine:

Under the cover of the night
In the silent harbor
Two lovers, lips sealed on each other, reunited after two long years…
True love never dies…

The fiance of the witch Meru is a sexy and wild werewolf?!

The witch Meru and her werewolf fiance, Riku, should have been married...but on the day of the wedding disaster strikes! A spell that the magician Nazo was casting accidentally hit Meru and she transformed into a little kid!! The only one who can return her back to normal is the one who cast the spell and Nazo has quickly escaped. What happens to Riku on the quest to find the missing magician? And how does their love stretch with Meru stuck in a little girls body? Will things ever go right for this unlikely pair??

Extras:

V.3 - Saigo no Onegai
V.4 - Renai Gokuraku Joudo
V.4 - Koigami - Love God

The hero in this manga has a split personality and each personality has its own lover! Aki is a right-hander and seme (but he denies his homosexuality); Ao is a left-hander and uke (acts as the "bad guy" and reduces Aki's excess stress). One personality is afraid the other one will take over and destroy it. In the end, which will win? Ao feels he will be deleted by Aki and asks Sayuu to help him...

1. Canvas ni Kuchizuke (w)o (Kiss to the Canvas)
Chapters 1-3 tells the story about the explosive encounter between a boy who loves that people watch him and an artist who loves to paint.

2. Canvas o Dakishimete (Embracing the Canvas)

3. Canvas ga Itoshikute (The Beloved Canvas)

4. Itoshii Yubisaki (Beloved Fingertips)
Kazune's childhood fascination with harpsichord tuner Takayama's fingers has grown into an obsession over the years. Now a high school student, how long with Kazune be able to repress his feelings for the cool Takayama?

5. Goshujinsama to Yobanaide (Don't Call Me Your Master)
Being mistaken as a girl and groped often Midori is getting sick and tired of it. Then came Fujita who is kind and keeps his distance no matter how much Fujita truly wants to touch Midori. Knowing this Midori is touched that such a guy exists. With this will love blossom and what's this... Midori is Fujita's... master!?

6-7. Kitsune no Yome (Bride Fox)
During a summer festival in middle school Akane is cornered and molested by a guy in a fox mask. It's also the night his best friend Kyouhei stopped speaking to him. It's three years later and Akane still can't move past that night, the unwilling pleasure he received at a stranger's hands, and the look on his best friend's face when Kyouhei saw Akane's ravaged body.

From Dan of Population GO:

"This charming story follows Kanon Miyamoto who, ignorant of her popularity, is confessed to by Bessho Chiaki, the school's most intelligent and beautiful girl."

From Aerandria Scans:

Kayuu, a doll-maker who was murdered six years ago, made living dolls at the request of clients. Mitsuki, his daughter who is still finding out the mystery to her father, together with her favorite student Yue, are faced with countless ordeals. What is Kayuu's hidden secret?

Two twin brothers Ry and Key were trained in martial arts since childhood by their Martial Arts father, "Rokuu Riley" as they are now young adults a tournament begins in their city and they feel they are called to accomplish something much greater in life. And in their own ways they will not stop until they have succeeded no matter what challenges, threats or obstacles come into their lives.

From Infinity Studios:
Ever since we were children, we’ve heard stories about ghosts and about heaven and hell. Well, what if we told you another existence between heaven and hell exists? This is exactly what Suh Rin, an average high school girl, finds out one gloomy day.
On her way home from shopping around, Suh Rin meets with an unfortunate end when she is hit by an on coming truck. The next thing she knows, she’s being abducted by a stranger. Overwhelmed by the fact she had just been killed, Suh Rin has difficulty grasping the fact that she has entered a new existence in a realm of spirits. More importantly, she has yet to realize that tremendous supernatural powers lie within her… a power great enough to make her the target of abductions by tremendously powerful people within the spirit realm.
However, thanks to Young and the mysterious owner of a café called the Café Occult, Suh Rin is rescued from a new existence as someone’s servant. On the contrary, she joins Young on action packed thrills in which she assists Young fulfill requests as an ‘errand boy’ taking care of special requests by clients in a lawless world controlled only by power.

Listen to the world's various stories on Yoo Si Ae's radio show, Cactus and Radio.

Tomoe Tatsumi is a freshman attending university in Tokyo. Life couldn't be better: he's living in a really nice apartment for less than most people pay for a single room. This is all thanks to Mitsugu Kurokawa: salaryman, landlord, and (hopeful) lover.

It is due to Kurokawa's generosity that Tatsumi is able to live in Tokyo on such a tight budget. Kurokawa's intention is clear: to love, honor, and cherish Tatsumi until his dying days! And if big brother Souichi Tatsumi has his way - that day will come sooner than not!

For Kurokawa, progress can only be made by "challenging the impossible...." And thus, Takanaga sensei introduces us to her charming romantic comedy, Challengers!

- DramaQueen

The main couple from Koisuru Boukun also have a few short chapters through out the manga that take place before Koisuru Boukun starts.

A manga consisting of a 9 chapter story with 3 side stories.

Shinju no Kusari (Chain of Pearls)
The beautiful, genuine pearls we lust after belong in a chain... because that is how they bind our hearts. Hisa, the newest manager of her high school's soccer club, has a secret: a part-time job. If anyone knew, she would either have to quit the job she needs to survive or the sport that she loves. Sakyou, one of the team's most talented and anti-social members, finds out about Hisa's secret... so it's a good thing for Hisa that the handsome and high-handed Sakyou wants to keep her close to him! Or is it? (There is an additional one-shot of this story in Vol. 1 of LoveSupreme Principle)

A "Girlfriend" with Substance
(scanlated as The Fruit Called Grapefruit)
Minami Kanan's debut work. Sachi was so determined to become Takanori's girlfriend that there was no way he could say "no." Literally, no way. She's the girlfriend he was forced to have, and he treats her as such. They go out together, but it seems obvious that Takanori hates every moment of it. When Sachi finally has enough of his unaffected attitude, will it make Takanori happy to be alone again?

Unconditional Love Formula
Tachibana Kouya is a whiz kid, while Ayumi barely passed the entrance exams. They're at opposite ends of the spectrum, but Ayumi is determined to win Kouya's love by having him tutor her -- then, when she passes the physics exam, she's going to confess. Why would Kouya want to tutor such a poor student, though? Ayumi's love rival discovers that Ayumi had to bribe Kouya to do it, and so she feels no remorse when she ruthlessly foils our heroine's efforts to succeed in physics and love...!

The Rumored Natori-kun
High school freshman Ai just found out that the stranger she fell in love with at first sight is the notorious Natori-kun, who goes to her school and is rumored to ditch every girl he agrees to date. That doesn't discourage Ai, though, because he's been nothing but nice to her so far. What will it take to become Natori's girlfriend, or is Ai doomed to become just another rumor?

Cecile wakes up one morning with a boy from her university beside her. Exactly how much did they drink last night? And now what are they going to do?

From Esthétique:
Campus comedies weren't always the leading plot of shoujo manga. The old shoujo manga used to focus on personal accomplishments, or becoming somebody. "Catch, Love" is about a girl who picks up a camera someday and realizes that she wants to be a photographer, like her father once was. She starts working for a magazine, meeting some celebrities and taking photos of them. But those old ladies chastise the girl because she falls short to emulating the great photographer, her father. She aims to perfect her skills and win compliments from those who loved her father's work... And of course, she receives a lot of support from her friends and the love of her life. A lonely heroine can't make a good story!

From Condensation:
The story centers around Keito Aoyama, a former famous child actor. Due to a childhood incident, she retired from her career early and withdrew from normal society. Now 16, she passes her days in boredom and without purpose. But one day she runs into a stranger who takes her to El Liston--a free school for high school students like herself, who don't have a place where they belong. Though hesitant at first, Keito decides to enter El Liston and subsequently, she begins a new stage in her life. With the help of her only remaining childhood friend, Taiyou, and her new classmates Rei, Momiji, and Kouichi, Keito slowly finds the courage to open up to others and to accept their support. Will Keito return to acting? Will she find true friends? Love?

Sequel to the novel River's End (Novel).

Yorozu lives in a love hotel. When a film crew comes to the hotel to make an AV, he has an encounter with Togame, the director. On the first day, Yorozu is asked to be a substitute actor and has his pants pulled down; it was the worst first impression ever! To make matters worse, he's worried about the openly gay Togame getting close to his younger brother, Satoru. Yorozu takes action and tries to keep Togame away from his brother, but...

A gripping reinterpretation/adaptation of The Illiad by Homer that revolves around Priam's daughter, Cassandra, who was believed to have been given the gift of prophecy by Apollo when he proposed to her.

By anonymous:
Nohae has been crushing on Dona, his neighbor, since they were younger. Dona is a girl who was obsessed with money as a child and would make her childhood friend Nohae actually pay her. Time has passed and now she's a teen, broke and living on the streets with her dad. Her dad meets Nohae and arranges for Dona to live with him. But Dona's not your typical heroine. She's one of those fake people, maintaining a perfect image at school but in front of her parents she's self-absorbed, a glutton, and is quick to nab a meal or swindle money. She's quick to anger and has a grudge against Nohae, but he likes her so much he's completely unaware.

In the Carramer no Yumemonogatari series (カラメールの夢物語シリーズ), also called "The Carramer Legacy" series: 1) Princess e no Tabi (プリンセスへの旅; Journey to the Princess) / Crowns and a Cradle When Prince Josquin de Marigny swept struggling single mom Sarah McInnes into a limo, he revealed a secret. Sarah's father had been in line for the Valmont throne -- and now her son was the heir! The brooding, blue-eyed prince promised Sarah everything she'd ever dreamed of if she would remain in Carramer -- except his heart.... Baffled and bewildered by the sense of homecoming, Sarah was torn. Josquin had given her a new family, but he'd also investigated her past, lied to bring her to Carramer and he'd be regent for her son. So once he took her in his arms, could she trust the promises he made? 2) Koi wo Wasureta Prince (恋を忘れたプリンス; The Prince Who Forgot His Love) / The Baron & the Bodyguard Watching over him... Playing royal bodyguard to Mathiaz de Marigny, the seductive Baron Montravel, was a temptation few women could resist. But the moment he was out of harm's way, Jacinta Newnham had fled his château -- and abandoned memories of moonlit nights that left them both weak with unfulfilled passion. Now stricken with amnesia and in danger once again, Mathiaz summoned Jacinta back to his side. Jacinta vowed to protect his life, but the greater peril was to her heart -- and the haunting secret she could never reveal. When the truth surrounding Mathiaz's accident -- and Jacinta's connection to it -- surfaced, would he force her to leave, or refuse to let her go again...? 3) Prince no Shukumei (プリンスの宿命; Fate of the Prince) / The Marquis and the Mother-To-Be Back in her lush, beloved Carramer, Carissa Day purchased the perfect B and B for raising her babies-to-be. Trouble was, an aristocratic "intruder" proved she'd been swindled -- her new home was actually his royal lodge. Worse, he proved to be Carissa's teenage crush, Eduard de Marigny, Marquis of Merrisand -- now more irresistible than ever. Penniless and pregnant -- with triplets! -- Carissa had to flee. Eduard, however, had other ideas. Namely, a partnership giving Carissa a title and protection -- and giving him an instant heir. Still, even with reignited passion burning between them, even with a kingdom at her feet, could Carissa wed her first and only love -- and forever forsake having his heart? Descriptions taken from FictionDB. Note: These are #4 - #6 of Valerie Parv's The Carramer Legacy series.