From Manga Art:
Miyu, whose mom was chosen to be an astronaut, was sent to live with Kanata, a boy she just met. Soon after, Kanata's father leave the two to live alone. Amidst the panic, a mysterious UFO came... and out popped Ruu and his babysitter-pet Wannya. For the sake of Ruu, the four of them start living together......

Every year the flowers bloom. Mysterious Cherry Blossoms blooming all over a crescent shaped island. That island is the island of Hatsune...

The main character who goes to Kazami Academy, Asakura Junichi, has the power to see the dreams of other people in his sleep. He was also taught magic by an old lady that allows him to create sweets.

One day, Junichi seems to have seen someone`s dream again while he was sleeping. Inside that dream, a girl who was a childhood friend of his appeared. But, he was woken up by his sister Asakura Nemu, forcing him to come back to his regular life. Nemu doesn`t actually have any blood relation to Junichi but their bond is deeper than other real brothers and sisters. So deep that it gives the illusion that they`re lovers.

It was another peaceful normal day waking up early in the morning and going to Kazami Academy. Together with childhood friend Amakase Miharu, the academy idol Shirakawa Kotori, the two sisters Mizukoshi Moe and Mako who prefer eating nabe on the school roof for lunch. Going through their day as usual, their childhood friend, Yoshino Sakura, who they thought had moved to America suddenly appears. It was a surprise for Junichi and Nemu. Sakura tells them, "I came to fulfill the promise we made when we were children..."

Cynthia comes from a family of assassins. She acts as a part-time student who's bald (she only appears that way), and she continuously receives orders from the organization to assassinate people. The story opens with her and two friends going shopping for hair growth solution, when a new mission comes up. Her master, who taught her everything she knew three years back, was hired as the target's bodyguard. The two must fight, but what will the outcome be?

When he was younger, Kujou Kiyosumi was incredibly awkward and nerdy. One day in elementary school, he courageously confessed his love to a girl, but she told him in front of the whole classroom that he was "disgusting" to be around.

Shocked, Kiyosumi asked the coolest guy in the class, Sagiya Maki, to help him become more likable, too. Thus began the days of training and now in high school, he had finally achieved most popular status alongside Maki. Everything seemed to be going along smoothly until...

Honey Kisaragi is a normal catholic schoolgirl. That is, until her father was murdered by the Panther Claws who were seeking the Airbourne Elemental Fixation Device. She then finds out that she is actually an android created by him with the Airbourne Elemental Fixation Device within her. She is now trying to live a life as a normal schoolgirl and seeking revenge against Panther Claw.

Sumi is in love with Mitsuru, but he doesn't seem to be interested in her as a woman. Determined to look more sexy and mature, Sumi takes an experimental growth hormone that her scientist father has been developing. However, the medicine backfires. Instead of changing into a buxom femme fatale, Sumi changes into a beautiful young man! She--he--is so gorgeous and so cool that even Mitsuru begins to take notice. Although the new situation with Mitsuru is imperfect, Sumi discovers that she can be closer to her crush: they can talk man-to-man. Yet, being Mitsuru's friend also has a downside, particularly when he reveals that he is in love with a girl in his grade!

Seung Hun is a handsome playboy who's never experienced true love. Woo Sun is a charming playgirl who wants to be loved for herself and not her beauty.

Jong Yi is the beautiful, mysteriously childlike and vacant boy who becomes the object of their affections. A complex love triangle evolves between these three, further complicated by the involvement of Jong Yi's unfailingly devoted childhood friend and first love, a girl named Yu Ri.

They're all soon to discover that love is a long, painful path...especially if the object of it is completely oblivious to your attentions!

Note: As indicated by the genre tags, there are both shounen-ai and romance pairings in this story. It is not F/M romance only.

From Go! Comi:

When her grandmother passes away, high-school student Kajitsu Toda suddenly finds two hot stepbrothers and an adorable little stepsister dropped in her lap! Kajitsu and her step-siblings have only one thing in common: they were all abandoned by their parents. Against the odds, they've pulled together to form a family without grown-ups. They don't want charity, they don't want pity... they just want their dignity!

Things are particularly tough for Kajitsu and her step-brother Natsu. As kids, they were as close as any true siblings. Now, reunited for the first time in seven years, they've grown as far apart as two people can be. Can they ever become friends again? And can two high school students living together, even as "siblings" ever escape scandal?

From Selene Scans:
Ogata Natsuki is the best player on the Kakuchi Junior High Basketball Team. Which is not saying much because they couldn't even get through the 3rd round of the Prefectural Tournament from freshman year until the end of Junior High. For High School, his friends convince him to try out for the Number One High School Basketball team, Fujiwara Academy. So he goes to live with his aunt who runs a hot springs resort to go and try out for the best. Fujiwara Academy.

The thing is... he's small. So people look down on him and he has trouble convincing people he's any good. Through one thing or the other, he ends up with Tachibana Mitsuki watching her school, St Mariannu High go up against Fujiwara Academy in a practice game. But the thing is, St Mariannu is very weak. Weaker than even his former school. Fujiwara is just toying with them and now they don't even want to finish the game. What will happen now? Will Natsuki ever be able to achieve his dreams of being High School Basketball's Number 1? And will it be with Fujiwara?

Yuuki Ashikaga is a high-school freshman at Sakakino Academy. While working as a student librarian, he grows enamored of Kotonoha Katsura, a girl who frequents the library. Unfortunately, Kotonoha is already dating Makoto Itou, another schoolmate.

The situation is further complicated when Chie, Yuuki's older sister introduces him to Roka Kitsuregawa, her kouhai in the basketball club. Roka becomes interested in Yuuki, who only has eyes for Kotonoha. In order to make him jealous, Roka lies and claims she already has a boyfriend, her former classmate Makoto Itou. Unfortunately for all of them, Roka's lie sets off a chain of events no one could have predicted...

Note: Cross Days takes place in the middle of the original School Days storyline and provides an alternate take on how things might have turned out.

From Attractive Fascinante:

Miyashita sensei was always an overachiever, but his perfect life was disrupted when he met his desired-filled student, Jindou. Trying his best to keep Jindou back on track, sensei had to guide Jindou personally as well as to fend off his ex-partners. Love developed as time went by, but sensei kept a distance from Jindou by trying his best to maintain an innocent relationship between them. Would Jindou succeed in breaking down sensei’s territory?

Moka's brother Megu is returning from New York City where he lived with their father. Not only that but she is also interested in the subject of art. When she goes to the library she meets Masato-kun, whom she begins to like. But Masato-kun turns out to be a playboy. Will Moka's determination win him over?

From Dan of Population GO:

Three friends, Kotori, Yuuto, and Rin are trapped in school when the principal halfheartedly summons a horde of demons. The demons make a pact with each student in exchange for possessing them. Most of the students wished to be be good looking or to have longer legs, but Yuuto manages to stave off the possessed student body while Rin overpowers the weak demon possessing her. Yuuto makes a pact with a demon to return the school to normal, but what will happen to the school now that each student is being possessed by a demon?

4-koma Based on a Novel - Date A Live.

Because of an unaccepted mariage, Norika has only had his parents for family. Unfortunately after his mother had passed away, he had to grow up on his own and to take care of his ill father.
Yet, after 15 years of silence, here comes the brother of his mother asking Norika to come and sign in a school located on an island while he would be staying with his father.

But the drawback of this school is that it is divided into two parts : wealthy people and not wealthy people. Hence the strong rivalry that has been born and ruled by the president of the students : Norika's cousin, Yuusuke.

Volume 1: Rio was living a perfectly normal high school life, when transfer student, Tomo-chan, entered his school. Rio watches as Tomo easily grabs the attention of the female student body. It's not until Tomo picks up Rio's dropped planner with a picture of his beloved idol, a male teacher, that they interact. Suspecting that Rio is gay, and after stating that he's going to "cure it" Tomo enlists in a "Homo Fixing Training Regimen". But does Tomo really want to cure Rio of his homosexuality, or simply get his undivided attention for himself?

Volume 2: Rio was filled with happiness when the cool transfer student Tomo-chan confessed to him saying, “I’ve always loved you” However, for some reason Tomo-chan has had a cold attitude lately. Since he had never been clearly told, “Go out with me,” Rio has become unsure about their relationship. Moreover, there’s a rumor that Tomo-chan is going to study abroad… When even Rio’s first love, big brother Haruka, shows up; will the two of them grow even further apart…!?

Volume 3: Will Haruka, Rio's first love, find adult love in this side story spinoff of the much loved Darling series?

Volume 4: coming soon

1) Hoshi sae mo Nemuru Yoru by Miyuki Kitagawa
(The Banquet of Stars) Kana goes along with her friends on a trip for Golden Week, and they happen to visit an island that she had once seen a picture of the stars from.

2) No Panties Musume by Ako Shimaki
Roux comes from another country and lives with Ichiko, a smart player who fools around with all the girls. She doesn't wear panties because it's not a part of her culture...? And kissing is a casual greeting!?
(Also included in Boku ni Natta Watashi vol 2)

3) Tomodachi Shikkaku by Akane Kasuga
Riku, a cute girl, steals the attention of all the girls from a jealous guy. He doesn't see her as a real girl, but she still likes him.

4) Koi no Neiro by Shin Yumachi
(The Melody of Love) Chizeru believes that Kaitou hates her, and is therefore scared of him. Things just aren't what they seem on the surface though.

5) Yuuwaku Lesson Itashimasho by Hina Sakurada
(A Lesson in Temptation) Himawari has never had a boyfriend in all her seventeen years, and she has also rejected every person who has ever confessed to her. But when she meets her new, shining and beautiful student, Taiyou, all reason just flies out the window.

6) Platonic Porno by Komomo Yamada
The go-to girl for love advice has never had a boyfriend? Her geeky chameleon teacher finds out, but how? How can a chameleon teacher also be an erotic novelist?!
(Also included in Kojin Jugyou)

From Intercross:

For all of Mao's life, she has longed to be girly and have tea parties with beautiful girlfriends. And finally, she has that dream right in her reach, until she walks in on three boys changing at her private all girls school... What's a girl to do when another girl she admired turns out to be a guy?!

From Shoujo Crusade:

Karin HATES guys. She can't stand the sight of them, let alone be near them. But after a near death experience she finds herself waking up to a guy she doesn't know, within a guy school and in a guy's body!!?!