From ShoujoMagic:
1. 38°C
Taiji's normal body temperature is 38 degrees Celsius, or so he says, but Shiina thinks he's full of it. Taiji is a friend with whom Shiina can always--and does always--fight... Until Taiji unexpectedly confesses his love! Shiina begins to run a fever, but is that the only reason she's getting so hot...?

2. Solution Maze

3. Heaven in Jail

4. Winter's Aquarius

In this story, our heroine, Shinobu, is a female ninja in training. The only trouble is, she seems more interested in hanging out with her friend Kaede, and the fact that her ninja Master is a round yellow thing that pretends to be hawk isn’t helping.

From Tokyopop:

Akira - who later appears in the CLAMP School Detectives manga series - is a dapper, debonair young thief-for-hire who becomes the object of 5-year-old Utako's affections.

N/A

The student council president is gaga over the vice president, but her feelings may or may not be returned. In the meantime, it's up to the serious and by-the-book vice president to keep the flaky (but surprisingly effective) president on track.

After she died from an accident, Ria become angel No. 5623. She could not forget her life from when she lived. She misses Ban Ji Hwan, her boyfriend on Earth, day and night.
1 year later, Ria happened to see Ji Hwan's name on the death list, the list of every names who is about to die in 100 days. Ria begged high-ranked angels to let her save Ji Hwan. Ria entered the body of So Hae, a shy girl who is tired of her life, the opposite of Ria's personality. Enduring the bullies from step-siblings of So Hae, Ria did her best to bear everything in order to look for Ji Hwan. But when she found him, Ji Hwan cannot recognize Ria...

From Manga Updates An ordinary high school girl, Lin Seonu, unknown even to herself is actually a woman saint holding ancient power called the "Jade of Bango." On her seventeenth birthday, she obtained the power to see ghosts, and every morning after that she goes to school accompanied by the harmless and lovely ghosts. One day, however, Lin has an abnormal dream, and that evening, she encounters a terrible evil spirit. Shivering in horror, she is rescued in the nick of time by a handsome man she had seen in a dream. He frees the ridiculous power that had been concealed in her. He says that his name is In Mu, and that he is her fiance.

Two girls start their freshmen year of high school. However, the two girls after years of being together are separated. One of the two does not take this easily and her world falls apart.

7 Short Stories About Sex (spanning across 11 chapters):

1-3. 7 Daime no Tomari (The Seventh Generation, Tomari)
Tomari is a cursed woman who must do specific sexual things with her partner or the curse will kill her. Her partner, randomly chosen by the curse, is a guy called Naoki. He's pretty much willing to do whatever she needs, but Tomari will have to get past his incestuous sister Kyoko first.

4-6. Hajimete to,
A teenage couple, Seriko and her boyfriend Ogihiko, find themselves caught in a plot from her crazy yakuza family to make them lose their virginity together.

7. Sandy Go Home
Yoko returns from studying abroad in America with her sex-crazed roommate Sandy, and they both proceed to fight over who gets to have sex with her brother.

8. Mete Yunde
After their parents died in a traffic accident, Morote's two older sisters became insane. Is he safe in the house with them any longer?

9. Pastel Ivory
School kids have a sexual encounter in a bathroom.

10. Ninjia Shoujo Makari Tooru
When a ninja invades a girl's bedroom, he finds himself completely outmatched by her skills, both ninja and erotic.

11. 80D
A couple has a sexual exploit in a library after hours.

From Shoujo Crusade:

One day, while in search for more food, our heroine stumbles upon a jar of what looked like umeboshi; little did she know that it would bring her more than just a full stomach. The mysterious snack somehow makes her shrink and she can only grow back when she eats something (which is a bit of a chore if you're THAT tiny). And if that's not troublesome enough, she's also dealing with her crush who seems to like her best friend!?

Satou Atsushi isn't neglected by his family so much as ignored completely. Left to fend for himself, Atsushi fails to learn human speech and instead learns "cat language" and "Dog language" from the family pets. When he's eventually socialized with other children, his speech is stunted and his social graces leave something to be desired. But on his first day of nursery school, he meets a gloomy blonde with the same last name who seems to be a safe enough choice in a first friend. After developing a rather sizeable fixation with Satou Manato, he finds out that there his first friend is seriously ill and has a twin; Shuuto.

Years later, two other friends begin school and find that there are two Satous in their class too. Two Satous who, at first glance, could easily be mistaken for twins, but there's a bit more to things than it first appears...

From An Endless Story:

If you ride a train you can see there are a lot of different people. I wonder where they came from and where they are going. I've been able to hear many conversations and I wonder what kind of relationship these people have. I want to talk to them and ask, but I would be weird if I did so I just enjoy imagining it by myself.

Haizuka just wants to live a normal life, a peaceful life far away from all the trouble he's faced. But as soon as he starts highschool, an encounter with a girl and a strange creature destroys any hope of a peaceful life.

From Basement Leisure:

Kazuma is a shy high-schooler who happens to be gay, and in love with a popular and handsome guy,Ayase! A while later, Ayase befriends Kazuma, having found out that Kazuma is gay, and admits that he too is gay, and has the same feelings for Kazuma! Yet all Ayase does is have sex with Kazuma, causing Kazuma to feel insecure, will this relationship work out, or will Kazuma's and Ayase's heart fall apart?

Izumi starts high school on a low note. For some unknown reason, rumors refer to him as the notorious Izumi, a thug who loves to fight. The truth is dramatically different. Izumi is the housekeeper for his widowed father, and spends his after-school free time doing the shopping, cooking and cleaning. He doesn't have the time or energy for friends, so his bad reputation actually is useful.

But what is the problem with Segawa and Sawatari? Why are the school idols always being so friendly with him? Don't they know about his reputation? What sort of friendship do they have in mind anyway? Why does Izumi start to feel like a ham-bone caught between two hound dogs?

From Iskultrip Scans:

Japan wields the power of a new form of influenza so lethal that only one person out of a million can survive an infection. Kazuma, a man able to withstand the infection of the unknown virus, "Cherubim [kerubimu]," has obtained the power to save his twin sister from facing the influenza! While Kazuma saves other people's suffering by using his new power, he will also encounter many surprising and painful things… A serious and comedic story of new abilities begins!!

A world of supernatural where strong preys on weak. An Earth not just for humans.....and a strange ability!

Onodera Goushi is a high-schooler who isn't much noticed in other people's daily life. In a sense, his life feels like it would be the same if he wasn't around. Then one day while returning from school, he finds himself in a life and death situation where a strange girl named Honoka saves him by sending him to another world. He then gets sent to the "Demon Nation" where many non-humans live and where he is able to meet the Ma-Ou (Demon King) who is... an anime otaku?!?!

Han Summer (Yeuh-Reum) and Hyun Moo-Heum are very different from one another. While Moo-Heum is a brilliant, yet stunning son of a CEO of one of the most influential and extensive companies in the world, Summer, on the other hand, is a mediocre-looking girl - a plain Jane, who is just under an inescapable debt of 70 million! And to whom? It is none other than Hyun Moo-Heum! In the midst of this dilemma, a mysterious figure enters and intervenes with their lives. Could he be of any help to Summer or is he destined to make her life more complicated than it already is?