From ShoujoMagic:

Karate girl Seri tries to kick away her past in order to catch a new guy at a singles party, but Tamaki, a childhood flame from her old karate dojo, shows up to show off and makes her heart pound. Their reintroduction leads to a karate challenge, and if Seri loses, she must become Tamaki's "toy"...!? It's a game of love with more rivals and obstacles (and sex!--LOTS of SEX!) than either Seri or Tamaki could have foreseen!

Includes extra stories:

(Vol.02) Virgin Beast - Dumped for being a virgin, Katsuragi Mio decides to ask Virgin Killer, Tsukahara Masaho for help.

(Vol.03) Scarred Innocence - Naive Moeka wants to fall in love but Kamiya Shun might not be the nice guy she thinks he is.

(Vol.04) A Girl's Mischief: Love's Supreme Principle - Renai Shijou Shugi sidestory.

(Vol.05) Rescued Letter, Complicated Love - Nozomi delivers a love letter to Shigeyama Itsuya from her friend but...

(Vol.07) Ribon

(Vol.08) Flower of Despair, Thorns of Pleasure - Renai Shijou Shugi Sidestory. Takarai Kou's point of view.

A girl who wants to love, fell in love with a impregnable guy who refuses to love…

The club activities was everything for Yuka during middle school. But now, in high school, she will definitely get a boyfriend. She's very excited about it, but…?!

Until that day, until that moment, I couldn't imagine that our love story would end like that...
Yes. Everything started after that girl came into our town...
(Source: Chibi Manga)

Yuzuru is a fifteen year old girl who is attending her first year in Houjou Academy. At her summer job, she met a troublesome rich boy, Renge Kai, who is attending the same school as her. Kai is part of the Kugeka, a class opened only to the rich students of Houjou.
At the end of the summer break she finds out that she has become Kai's "Honey". This nickname is given to all the students from the regular class choosen by the Kugeka to become their assistants, so that the rich boys can be successful without any problem. The up side to being a Honey is that all their school fees will be taken care of.
Although Yuzuru's family has some financial problems, she doesn't want to accept her role of being Kai's honey. But the only way to quit is to leave the school... What is she to do?

From Tenshi-Tachi:
Tsukasa Miyu's life revolved around only one thing--swimming. She gets admitted to Tenkai Academy on a swimming scholarship. However, before the start of high school, she encounters Suzuki Aoi and gets drawn into a world that doesn't involve just swimming anymore...

From ShoujoMagic:

The beautiful, genuine pearls we lust after belong in a chain... because that is how they bind our hearts. Hisa, the newest manager of her high school's soccer club, has a secret: a part-time job. If anyone knew, she would either have to quit the job she needs to survive or the sport that she loves. Sakyou, one of the team's most talented and anti-social members, finds out about Hisa's secret... so it's a good thing for Hisa that the handsome and high-handed Sakyou wants to keep her close to him! Or is it?

Vol. 1, Side Story 1: A "Girlfriend" with Substance
Minami Kanan's debut work. Sachi was so determined to become Takanori's girlfriend that there was no way he could say "no." Literally, no way. She's the girlfriend he was forced to have, and he treats her as such. They go out together, but it seems obvious that Takanori hates every moment of it. When Sachi finally has enough of his unaffected attitude, will it make Takanori happy to be alone again?

Vol. 2, Side Story 2: Unconditional Love Formula
Tachibana Kouya is a whiz kid, while Ayumi barely passed the entrance exams. They're at opposite ends of the spectrum, but Ayumi is determined to win Kouya's love by having him tutor her -- then, when she passes the physics exam, she's going to confess. Why would Kouya want to tutor such a poor student, though? Ayumi's love rival discovers that Ayumi had to bribe Kouya to do it, and so she feels no remorse when she ruthlessly foils our heroine's efforts to succeed in physics and love...!

Vol. 2, Side Story 3: The Rumored Natori-kun
High school freshman Ai just found out that the stranger she fell in love with at first sight is the notorious Natori-kun, who goes to her school and is rumored to ditch every girl he agrees to date. That doesn't discourage Ai, though, because he's been nothing but nice to her so far. What will it take to become Natori's girlfriend, or is Ai doomed to become just another rumor?

When Aina, who does poorly at school, and Shinga, who is at the top of the class make love, and without knowing it, get the sounds they make broadcast live all over school, trouble may just be stirring and dark clouds may just be gathering over them. (Source: Rebellious Love)

Wealthy sixteen year old Oriyama Karin has never had a boyfriend before. With the expectation of finding herself a prince charming, Karin manages to fall on top of Tsuruki-senpai, a popular guy at school. Now she has fallen for him but, she doesn't want to make him her boyfriend!? She has other plans in mind.

Included one-shot:
Volume 4: Yowamushi Meikyuu

1-3. Shiiku Hime
Takanezawa Hime is a girl from a wealthy family. When she was small she started bullying Asakawa Nachi. Under Hime's guidance she wants Nachi to become her ideal pet. And thats why Nachi always obeys Hime's commands.

4. Junai Koza Kemono Shiyou
The protagonist has to teach to a boy who was her childhood friend when they were little but now the boy turned into a beautiful guy and rather than studying he prefers...other things!

Story 01) Kakene Nashi no LOVE Torihiki (A Love Transaction without Overcharging): Since Ami Kirisawa's father passed away, she's had to make it on her own. Now she's built a reputation as an enterprising young woman who will do anything for money. However, when Ruka Hakomori (of the Hakomori Financial empire) makes assumptions about how much of Ami his money can buy, Ami fearlessly proves him wrong. Ruka decides he wants her to help him get out of a marriage interview, but opposing Ruka's ruthless parents isn't going to be easy, no matter how fearless Ami is.

Story 02) Kokoro Goku Ama-jitate (Very Sweetly Cut Heart): Suzuko runs into Riki-kun while shopping for Valentine Chocolate. When he learns that she doesn't have a boyfriend, he asks her to give him chocolate that day. The two become close but will Riki-kun's fanclub grows jealous and will do everything they can to separate them. Will they succeed or will love triumph?

Story 03) Kyokou Shinwa ~Sekando Reipu~ (Made-up Myth ~Second Rape~): This is a serious story about the effects of rape. Wakana is a shy and unspectacular girl who has been text messaging the spectacular Taku for three months. Suddenly, Taku suggests that they meet, and when they do... he rapes her. Wakana goes to the police, only to go through "second rape" -- the doubts of others who think she brought it on herself.