From Seven Seas:

Tor Kokonoe has entered the prestigious Koryo Academy, a high school dedicated to training its students to wield Blaze―individualized weapons that a student manifests. The future of a student is often shaped by the form their weapon takes, and when Tor’s appears as a shield, suddenly he’s the odd man out. But that’s when the Duo system comes in, a program where students are paired up. Teamed up with a silver-haired girl named Julie Sigtuna, Tor’s adventures at Koryo Academy are just beginning!

Mysterious murders have been taking place in town lately and everyone is uneasy. Anne may look like an ordinary teenage girl in plain human’s eyes but she has something unique that attracts Vampires. May it be her blood type or even something in her skin that makes vampires so attracted to her? No one knows... One thing is for sure, Vampires keep coming in the city she lives in and they are even in her school now! Luckily for her, she has her brother to protect her and also one mysterious new guy...

Two decades ago, the dragons returned to earth. Soaring above the skies leaving behind trails of destruction. They attack humans for the simple reason, their destructive impulses. In order to fight the dragons, humanity acted. They began to dabble in magic...

High-schooler Shiina Shinya thinks that all girls are pretty much good-for-nothing, mostly because he doesn't understand them at all. That doesn't stop him from being surrounded by strange girls.
Tsubasa Tooka, a cute, much-admired girl, stalks him. Shikimura Masami is majorly into masochism, and has recruited Shinya into her play sessions. Ikari Satsuki seems suspiciously interested in the recent serial stabbings, and seems to want to drag Shinya into it. Banjou Yoruko, a normally quiet, bookish girl, has decided she and Shinya are bound up in some fantasy setting. Uchida Yumeji is the school's sleeping beauty, who spends all of her time in the infirmary because she requires so much sleep. Shinya brings her newspapers, so she can keep up with current events in the short time she spends awake. Lastly, Okui Akane is convinced she is a vampire. For all Shinya knows, it could be true, but in practice it just means that he has to let her drink his blood.
How will Shinya deal with all these good-for-nothing girls that complicate his life?

Mihama Academy - on the surface, a closed learning environment established to nurture students who find themselves at odds with the world around them; in actuality, an orchard-cum-prison built to preserve fruit that has fallen too far from its tree.

Whatever the circumstances behind its establishment, Mihama Academy is at present home to five female students, all with their own reasons for "enrollment." For better or worse, each girl has established a routine obliging of her current situation; life moves at an idle, yet accommodating pace within the walls of Mihama.

Yet with the arrival of the institute's first male student, the nearly preposterously opaque Kazami Yuuji, the students at Mihama begin to fall out of step with their predetermined rhythms. Will Yuuji prove to be the element the girls around him needed to take hold of their lives once more, or will the weight of their pasts prove too steep a wall to overcome?

Based on the visual novel of the same name by Front Wing. This spin-off focuses heavily on Yumiko Sakaki's story.

Koizumi Yuta is a 14-year-old boy who has quite a bit of a problem. The demon princess of the magical world, Lucia, has to procreate with him. That child would have the ability to engulf the entire world for seven whole days. Mikamoto El and Kasukabe Rie are the two angels assigned to make sure that doesn't happen. Kasukabe Rie happens to be the girl he likes. Just how is he going to survive this ordeal?

Note: Included in the limited fourth volume edition is a special collaboration booklet (comic) between Princess Lucia and Kimi no Iru Machi.

From MangaHelpers:

Based on an ero-game by the same name, Melty Moment follows Takeru as he gets closer to several girls in high school. He ends up leading an election committee that is filled with cute girls. There's shy little Natsuki, serious little Misao, his childhood friend Yuuka, classmate Sumire, and talented Aoi. Who will he end up with? [tethysdust]

Kohinata Kanade is a second year violin student at Seiso Academy's Music Division. She lives together at the school dorm called Linden Hall with her childhood friends, brothers Kisaragi Ritsu and Kyouya. They practice intensively day after day at their orchestra club, aiming for victory at the nationwide music concours. However, one day Kanade is told by a boy she doesn't know "Your performance has no flower"?!

An anthology comic of Infinite Stratos by various mangaka.

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.