From MangaHelpers:

Shun knew what to expect when he became a high-school student. As he entered the gates of his new school, four beautiful girls suddenly surround him. These four girls are the same four girls he grew up with since kindergarten. The four girls are Rio the athlete, Miku the cook, Nana the nerd, and Yuri the student president. These four girls will be battling it out between them in order to win the heart of their beloved Shun.

The story is set at Shishidou, a school attended by rich and elite people. Tomu Shirasagi, a gambler, is a mysterious new transfer student who has come from a public school (instead of a prestigious private one) and faces the elitist environment. There, he declares a challenge toward any student and claims he will bring to the ruin the whole school through a series of gambling matches. Nobody knows why he has come to that school or what the real motivations behind his actions are.
During any match, Tomu shows off all of his unique coolness and ability.
He employs a wide range of tricks, both psychological and physical, to ensure his victory. In any game, you will constantly ask how he's planning to win, why he's really doing certain things, and what's really going on. At the end of the matches, the tricks are revealed, and they all work in real life, even if they do require one to be highly skilled or lucky in order to perform them.
The story centers around the various matches he undertakes and the interactions between the various characters, like Mika Shishidou, the beautiful granddaughter of the school headmaster, who is highly intelligent but contemptuous and superb, or Abidani, the vampiric looking dorm superintendent and main villain (for now) in the series, who has a sadistic personality and whose goal is to make Tomu leave his school (or to get him killed).
As the story unfolds, more about Tomu's past is revealed, leading to unpredictable turns of events.

Yukiteru is living with his family friend Yuno after a fire burnt down his home as a child. They live their life until a fellow classmate Rena who is jealous of their close friendship makes a surprise move.

From DeNA:

Our protagonist Haruka has been given the gift of precognition. He’s led an ordinary life so far, without really giving question to his special ability. However, one day, he foresees someone close to him die in an accident while travelling. It’s only after he sees this insufferable vision that he gathers the determination fight against the future, but… in such an unthinkable way. What will the future hold after Haruka rises up against a fate that’s already been decided…?

Gosh?sh?-sama Ninomiya-kun's story revolves around Shungo Ninomiya, a male high school student trained in difficult hand-to-hand combat. He lives in a huge house with his older sister Ry?ko, who is almost always gone on some dangerous mercenary mission. One day, his sister sends Mayu and Mikihiro Tsukimura, two siblings, to live with him to help Mayu overcome her fear of men. Unfortunately this is accomplished by making Mayu and Shungo share the same room, bathe together and even sleep together in the same bed. Making things even worse, Reika H?j?, the student-council chair, is blackmailed into becoming their maid due to a video that Ryoko recorded, in which she tries to seduce Shungo. ~from Wikipedia From Baka-Updates: Shungo is a normal high school student living in a huge house. One day, his sister Ryoko sends Mayu and Mikihiro Tsukimura, two siblings, to live with him to help Mayu overcome her problem. Mayu's problem: androphobia (fear of men), and Ryoko wants Shungo to help her overcome it. How? By making Mayu and Shungo share the same room, bed, and even take baths together. To make things even worse, Reika Hojo, the student-council chair, somehow ends up becoming their maid.

Kurata Yuki is staying alone at home while his parents are off on their vacation. His childhood friends Nekoyanagi Mei and Inui Sayo are helping him with the household stuff in the mean time. Mei is outspoken and active while Sayo is calm and knowledgeable. They have known each other for their entire life and they treat each other like they were real siblings. Little do any of them know, they’ll be involved in a love triangle a year from now.

The Kirionira are the demons that live in another dimension and invade the human world through people's dreams. The only defense humanity has against the demonic assault are the hunters who rely on their sex drive as a source of power to fight against them.
Riku Yoichi came from a long line of hunters and had high amounts of sexual energy which allowed him to be a great hunter. He moved away from his home town after middle school to demolish the Kirionira and was successful in finishing off the king and ending the battle forever. However, the peace came at the price of Yoichi losing his sex mojo.
Returning back to his home town, he soon learns that the demon invasion was not over, but without his sex drive, he is helpless to fight back. He tries convincing his childhood friend Namba Midori and her female classmates to get him sexually aroused, but they want nothing to do with it.

Takasaki Tomoka is a young girl seeking love. She had finally found her prince and slowly began to think of a way to speak to him. Tomoka met up with her childhood classmate from piano lessons, Miyazawa Arata and was invited to a performance by his band. There, she met the prince she had been admiring for many days. After becoming drunk, Tomoka confessed her love to her prince but problems arise with Tomoka having to take her love down through a dangerous path.

From Nagareboshi Manga:

Kitazono Meiko falls asleep in the library one day, only to be awakened by a kiss! She is unsure of who it was that kissed her, however, since there are multiple boys still in the library. Could it be the popular boy Shinoda-senpai? Or the super-cool Mikoshiba-senpai? The boy-next-door type Mogami? Or the cute underclassman Hachiya? Who could it be? They're all possible candidates, but which one does Meiko like the best...?

Oneshot in volume 1:
Soprano (released by Ouiratsuike)

Oneshots in volume 2:
Anna no kami ga nagai riyuu (released by Sound of Jewels)
Hakka drops (released by Sound of Jewels)

During the early 20th century, along with technological advancements, scientists were able to develop sophisticated magic. The combination of science and sorcery was Makinot, circuits made from spells that were put into objects to bring them to life and even gain a personality. It was developed as a military weapon and has now spread throughout the world. Akabane Raishin is now attending the Royal Academy to become the best in the world. Accompanied by the lovely teenage girl Yaya, who is actually Raishin’s puppet weapon, he plans on rocketing to the top of the class. However, his test scores come nearly dead last although his combat skills and determination are second to none. Raishin has to compete with the deadliest of classmates if he wants to come out as the king.

From MangaHelpers: It is still a shock to Saga Shigekata that he is standing at Ikebukuro Krea Academy, a relatively new school with a very particular curriculum. He was supposed to be attending a normal high school, but when his parents discovered the sketches he was drawing, they sent him here. This school is relatively new and is known as the otaku school where aspiring manga artists gather to learn about creating their own masterpiece. Shigekata meets a fellow first year named Miyakawa Hinari who seems to be in a cosplay costume but later finds out that not only is she Shigekata’s classmate, she is the president and founder of Krea Academy. He starts making new friends that inspire him to produce artwork with a lot of passion. [vyc]

The Golden Dragon has sent the legendary sword into the world so that, when Black Dragon that is bound to come to destroy the world appears, a hero might take hold of the sword to slay the world-destroyer before his foul designs are wrought. Who could possibly wield the sword of legend to become the hero of legend who is fated to engage in a fight of legend with the evil dragon of legend?

As time reveals, Alfonso, an elder of the village, is and always has been the chosen one. And now, as the fated hero of legend, he must lay aside his elderly ways and stride forth on his quest of legend and find the Golden Dragon of legend so he may gain the powers of legend to defeat the Black Dragon of legend in a legendary fight to stave off the legendary armageddon.

It's going to be a legendary adventure.

Rintarou is deeply judgmental of women, and hates that his dad has been cheating on his mom with a female neighbor. He does not want to be like his dad, and his thoughts are full of gendered sexual slurs towards his female classmates. The only exception is the most modest girl in his class, Yatsugi Azusa. A mosquito-borne disease seems to be spreading around among the women in his city, whose symptoms are fever and extreme sexual aggressiveness. Will he and Azusa make it through the epidemic?

From MangaHelpers: This is a manga based on a popular light novel series of the same name. Kazehaya Kamito has been summoned to the girl's school Areishia Spirit Academy, which teaches noble young ladies how to make contracts with powerful spirits. On his way, he has the misfortune of catching sight of one of these lady spirit contractors bathing. She is Clair Rouge, and she is contracted to a spirit named Scarlet, though she has her sights set on a more powerful spirit. Kamito convinces her to lead him to the school, but she stops on the way to make a contract with this powerful spirit. When Kamito ends up 'stealing' the powerful spirit, it is revealed that he is actually an unheard-of male spirit contractor! What could be the origin of his power? Now Clair is determined that he's going to have to support her, since she believes that the spirit he now has power over what should rightly be hers... [tethysdust]

Junior High student Nao's brother complex is so strong, it's almost at the point of incest. She's determined to make her brother, High School student Shuusuke, see her as a woman. So determined, that she goes as far as going into his room to throw away all his non-incest related porn. But as she's looking for his porno stash, she finds a photo album... and she's not in any of his childhood pictures. What is going on? Reading direction: Right to left

Amano Keisuke was born under a special star. Ever since he was young, he has encountered thousands of "lucky sukebe (ecchi)" situations that tend to have him end up being slapped by girls. One night, a falling star crashes into his house. The star turns out to be the magical angel Lili and her sidekick Chapi. They have come to save the world from the 100 demon lords that plot to destroy humankind by utilizing the secret weapon hidden inside Amano's pants?

In the medieval fantasy world of Alfheimr, succubus princess Astarotte Ygvar--the first princess of the kingdom of Ygvar--has just reached the age of 10. In the coming years, it is necessary for succubi to obtain a male harem. To maintain their appearance, they must consume a substance only found on males called "Sauzfryma", better known as semen.
The princess, however, detests males and will only agree to create a harem if a human male joins.

From Paperdolls Project:

Hotaru Kunoichi of the Iga Village has accepted a request to infiltrate Oda Nobunaga’s castle, Aduchi Castle. Under the guise that she is the younger sister of Mitsuhide, Nobunaga's confidante, she investigates the Oda army for dissenters. Hotaru deepens her relations with great military commanders, from Nobunaga to Hashiba Hideyoshi and Tokugawa Ieyasu. However, it will all be over if they find out who she truly is . . .