After losing her parents when she was young, Rio has been supporting herself and her brother. Rio believes that it's useless to rely on others. One day, she buys a trump card of the jack of club, modeled after Sir Lancelot, believing she could gain good money auctioning it off the internet. That night she meets Sir Lancelot in her dreams, which recur every time she sleeps. When Yuuki-kun asks her to go out with him and nearly kisses her, Lancelot suddenly appears out of nowhere and says he has come to save her?!

From Nagareboshi Manga:

After being overseas for five years, 16-year-old Yamato comes back to Japan to find that her geeky best friend, Ai, has turned into a delinquent, and wants nothing to do with her! Yamato tries to revive her relationship with Ai while finding out about her troubled past without Yamato, and why she changed.

Miki-kun likes the girls in school. A lot. One day, he meets someone in class who shares his interest in girls...

1) Mint de Kiss Me
There is a legend that if you kiss the man you like with a mint candy in your mouth, you can become one with your love. Misono is a rather superstitious girl who decides to test this out on Tohno-sensei, a young teacher she has a crush on. Unfortunately for her, she makes a mistake in the attempt to surprise him and instead kisses her fellow classmate Shindou. Of course this would be the time for the legend to work quite literally as Misono’s spirit enters Shindou’s body.

2) Genseika
Chiya goes to school with her friends and witnesses one of them die suddenly as a flower bursts out of him. The three friends had been together since elementary school, the death hitting Chiya and Yutaka hard. When other people begin dying from the flowers, they investigate possible reasons for such usual deaths. To her surprise, she finds answers close to home.

3) Furimuke Romance!
The hero of girls targeted by guys peeking into the locker room, Taka has quite the violent tomboy reputation. But all she wants is for some handsome guy to ask her out. A cheerful street vendor, Ryouta gives her a special ring with a heart locket pendent to hold pictures. When two photos are enclosed, romance is in the air.

4) Hang in there Nakago
Involves the scenario where Fushigi Yuugi was actually done by real actors. Unfortunately, Nakago (stage name) is a lot more unconfident than the character he plays. At least his one main fan, an unnamed woman with flowers, is there to support him through his worries.

Moriguchi Orito is transferring to a new school, but being lost in the fog he can't find his way to it and ends up bumping into a beautiful girl and got struck by a vision of her in a very sexy pose. Seeing him with his cellphone in his hand, she thinks he took a picture of her and runs away crying, "My life has ended!", dropping her own cellphone in the process. Finally finding his way to the school, he realizes that it's full of very weird people, and that his new seat is next to an empty desk where a bag is hanging with the same strap as the one on the cellphone the beautiful girl dropped...

Tank has a different version of chapter 7 due to additional pages.

From Nagareboshi Manga:

Mai Kojima is a slightly ditzy sixteen-year-old, but she's gotten her first boyfriend! They've been dating for three months. Even though they should be at their most lovey-dovey, they haven't been able to make out at all… That's because her boyfriend Yu-kun is a super exam-taking student aiming for Tokyo University. Every day is an uneasy one, without much hugging or kissing.

From ShoujoMagic:

Ever since he was small, all the girls in the neighborhood have fawned over Tsutomu Yamaguchi, whose name came from a song and whose adorable face closely resembles the monkey character Monchichi's. Even back then, it was enough to make his friend and neighbor Mikako sick. Now that he's a little more grown, Tsutomu looks like the lead vocalist of Manbou, Ken Nakagawa (Midori friend/boyfriend from Tenshi Nanka Ja Nai; we meet main characters from Tenshi on market/fest), and that makes him even more popular with the ladies. But Mikako--now a trendy teen with modern sensibilities--couldn't care less. Or could she...? Gokinjo Monogatari is a sharp-witted and stylish slice-of-life story!

Continuation (after years) in Paradise Kiss.

From K.I.S.S.:

Coming to earth to live the high-school life he's always dreamt of, Hirito finds himself in a bathroom on top of a naked girl! It turns out she goes to the world renowned Konoeghara Academy. Hirito is shocked to find the school only consists of seven students in total! Why in the world does the one of the most prestigious academies in the nation only consist of seven pupils...?

Full-color one-shot about girls with guns.

From Nagareboshi Manga:

There's a jinx at Haruru's school - if a couple sees the blue train at 6 am together, they'll be together forever! But if a couple sees the blue train at 10 pm together, they'll break up!
Haruru is going out with Nagi, a boy who goes to another school, and their love is just starting to blossom. But what happens when Haruru happens to see the 6 am blue train with someone else?!

From DMP:

Haruka Iijima and his teacher, Nakagami Sensei, are in the middle of a bitter-sweet relationship. Being a student and teacher couple isn't easy, but they're about to find out that's the least of their troubles. Nakagami Sensei's family, the gang of impossibly beautiful, age-defying Nakagami Sensei obsessed individuals might just turn out to be the worst nightmare. Will this love be able to survive the perverted mystery that is the Nakagami Clan?!

In the series:

V.1 - Nakagamike no Ichizoku

V.2 - Akuma Kiru

V.3 - Kamenbutoukai de Aimaseu

Included oneshot:
Kuroneko to Waltz (Waltz with a Black Cat)
Hirose is mad. Once again his boyfriend Matsui has cheated on him, with the sorry excuse of: "Sometimes I wanna see a girl's boobs more than a guy's d*ck."
Crying at a nearby shrine, Hirose curses Matsui... And the next day, outside Matsui's apartment, he finds a black cat with a scar just like Matsui! And Matsui seems to have disappeared...

From ShoujoMagic:

Story 1: Automatic Angel
Serika, a high-school student, is known for being a well rounded girl with an attractive face and figure. She is clear-headed and has a talent for sports. But she's an... android!?

Oneshot: The Winter Was Trying to End
Tale of a high school professor and student.

Gorou has a crush on his older stepsister Haru. Unfortunately for Gorou, Haru happens to love teasing him sadistically in every way possible.
A 4-koma comedy about their wacky day to day life and interactions.

Hoozuki-san Chi no Aneki - Nano Shucchouban and 2 chapters of Hoozuki-san Chi no Aneki - Nano Branch are included in volume 3.

Much to her embarrassement, the shy Mashio-chan wins a set of couple tickets for the amusement park. She feels at a loss for what to do since she has always been bad with men. So what will happen to her when the drama club president Katokura Aki suddenly declares that he would erase her awareness...?

Prequel about Nishizumi Miho: her first meetings with her friends in elementary school and how she came to start avoiding tanks.

From Yen Press:
Michiru Kita’s a weak-spirited girl who has a hard time saying what’s on her mind. One day, she notices mysterious, ring-like markings around the necks of two of her classmates, Chika Akatsuki and Shito Tachibana — two boys who miraculously survived a horrible accident six months before. Michiru, possessing the rare ability to see these rings, knows that they warn of impending death. Thinking that, perhaps, she can do something to save her classmates’ lives, she approaches them…but it seems the boys have already made a different kind of deal and garnered themselves a heavy debt.

The male lead has gynophobia (fear of woman) due to a traumatic experience. Following the recommendation of his sister, who is a nun with little brother-complex, he enters a previously all female school that now has a 9:1 female to male ratio. Then the queen of the school demands that he work for her as her secretary! How will the gynophobic guy cope working so close to the queen?

One day, Nao's father suddenly announces shocking news! Because his friend helped him with his debts, Nao's father agreed to have Nao and his friend's son engaged! Nao is furious with this agreement and transfers to her fiancé's school, Kaei Academy, in order to make her fiancé break off the engagement. But how can Nao force her fiancé to break it off when she doesn't know what he looks like?! Join Nao in her quest to find her "husband-to-be"!!

From etc:

Eiko is something of a plain Jane and a doormat, while her best friend Moe is a head-turning beauty. Despite their differences, their friendship is as strong as ever.
Guys are always asking Moe out, but her answer is invariably "Only if you promise to put Eiko before me."

From Shoujo Sense:

The packed morning train isn't a good place to be if you're small; a fact that high schooler An knows all too well. So when a boy rescues her from the crowd one morning, she should be grateful... right? The only problem is, he treats her like a little kid! Who is her rescuer, and what will happen when she meets him again...?