4 Stories---The first and second story have the same heroine.

She works at a daycare center or kindergarten, and unknown to her colleagues she used to be a much feared female gang leader. ^-^ Also, the heroine has good vibes about a certain male colleague. One fine day, she meets an ex-male gang leader who knows her past...and events start unraveling from there.

For the second story, it's set in the daycare/kindergarten too. The main character is one of the kids in the kindergarten, and he has a secret which he is afraid to let other people know, especially his beloved teacher. (The heroine is his beloved teacher.)

Story #3
The main heroine is a 16 year-old girl. Her father is a scientist and always invents some weird things. What's more, he claims that he came from another planet! All these drive the poor heroine crazy ^-^ But at least now her love life is going fine...until the day 2 guys from outer space land on Earth, wanting to find out more about the 'Love disease'! Perhaps her father has not been lying after all?

From Tokyopop:
On a world with no women, the surviving men have reintroduced the female in the form of an android. Called Marionettes, they are built to serve men and are limited in their interactions with humans. That is until a poor boy named Otaru Mamiya encounters a Marionette named Lime. Lime is a Saber model with a special circuit that gives her emotions. When Otaru awakens two more Saber Marionettes, his life as an 'average' man quickly becomes as extraordinary as the lives of his eager, busty new friends.

The story revolves around Tsukune Aono, a boy who accidentally gets enrolled in a school inhabited by monsters and demons. He quickly befriends Moka Akashiya, a vampire who soon develops an obsession with his blood, and later meets other girls who soon take a romantic liking to him.

Shizuka, age 17, was raised by her mother, and the two are very close. However, the store her mom's worked hard to maintain was swindled by the Sakurasei Real Estate Company.
Shizuka then, pretending to be the new wife of the president of Sakurasei, enters the Sakurasei family home while the president is away on business to get back the deed to her mom's store. In an instant she becomes "mom" to three boys, and the eldest son Kanon is the same age as her...

From Enchantment Scans]: Zhui-Ming (Shina in original) is just an average girl. However, due to a makeover, she accidentally gets mistaken for popular idol, Ai, by another famous idol, You. What's this? Ai and You are supposed to be dating?What is going to happen to Zhui-ming? (found in the series Panic x Panic )

from Blissful Sin: The president of my company caught me, Chisato, kissing another man somewhere. Luckily, my company ranking is so low he shouldn’t be able to recognize my face! I desperately tried to convince myself of that, but several days later, I was selected to be the president’s secretary. This is horrible, it seems like the president knows about my relationship with men!

The story revolves around Wakame High School's extracurricular club, "Sexy Commando Club," which consists of 5-6 male members (one being the high school principal himself), a female manager, and a small mysterious pet (that may be extraterrestrial in origin). The strange and ancient art of Sexy Commando (the roots of which extend back into Japan's Muromachi period) is a martial one; however, instead of focusing on how to defeat an opponent with punches, kicks, or grappling, it focuses on how to distract the opponent. The logic follows that any distracted opponent is unable to fight, and therefore the art of Sexy Commando trumps any other form of martial arts. There are as many techniques as there are ways to distract, though Wakame High School's Sexy Command Club tends to employ the unzipping of the trousers (Elize no Yuutsu).

From ShoujoMagic:

All Kumiko wants is to become a teacher; however her father is dead set against it. He is giving her one chance to prove herself as a teacher before forbidding her from pursuing this career forever. Meet her newest student, Ryu-kun. He has NO desire to LEARN anything from his tutors, rather he is an expert at teaching THEM about...SEX?!

Note: The story was originally released as a single short story, but it later became a series.

All of the girls at his college love Suou Tsukasa and come up to talk to him on a daily basis. Unfortunately for them, Tsukasa hates girls that are straightforward like that, but is too nice of a guy to tell them that.

In fact, he has a crush on Kizaki Megumu, his classmate and one of the shy and least talkative girls. The professor in one of the classes they have together is Dr. Hime, a young teacher whose childish looks and short height makes her a target for her students to jokingly tease and treat her more like their friend rather than a professor.

After taking home the drunk Dr. Hime, who was served lots of alcohol by her students, Tsukasa learns a giant secret about her love life.

From Essence of Purity:

Takuma Ban, only son of the Ban familly from Hokkaido, comes to Tokyo on a quest: to find a fitting wife... with the help of Meari his cow. Jumping over a school fence while carrying Meari on his back, he unexpectedly meets a girl, Yuki Samejima. After one minute, he decides that SHE'll be his bride. Unfortunately for Takuma, Yuki's older brother, Ranmaru Samejima, is completely opposed to this.

Of course, the fact that Meari seems to have developed an instant "animal" attraction to him only reinforces Ranmaru's dislike of Takuma. Takuma is determined to make Yuki his bride and that, despite Ranmaru's stern "objections". Nevertheless, when not only Kei Enjouji but also Takuma's own family start getting involved, things get a little … "chaotic".

(Note: was originally debuted as a shounen manga, but Kodaka switched publishers and began writing it as BL)

From 801 Media:

Being with an older lover is hot on just so many levels... Seiji-kun is a novice manga artist. He's also completely addicted to the body of the incredibly beautiful Sono-san, despite the fact that Sono-san is a guy. Is this love? Along with the title story, one that paints a tale of youth and emotion, this volume is filled to the brim with stories of overwhelming density, including "Not Just When it's Convenient" and "Let's Go Home." A total of six stories in all.

• Onegai dakara, Kiss (w)o Shite (Please, Kiss Me)

• Otona no Tsugou ja Naikute (Non-Adult Situations)

• Gaki wa Sunao ja nee (Indirect Youth)

• Aiganbutsu wa Oheya no Naka (Trophies Belong in the Bedroom)

• Ouchi e Kaerou (Come Home)

1-2) Sensei to Himitsu
Kaji's woken up from his nap hearing popular Tsunoda-sensei getting hot and heavy with another guy! But it's his partner, the plain Aritou-sensei that Kaji can't stop thinking about. Kaji's eyes are being opened as he finds that the needs and dark desires that can bind together lovers aren't always about love...

3-6) Hold me for all of Time
A researcher, Sawatari Kaoru, runs off after finding out that there will be no more funding for his research. As he wanders around he sees an abandoned warehouse where he could use to continue his research with his remaining savings. As he walks inside the building, he meets an arrogant little boy. Surprise ensues as to the boys identity, and the unexpected result of his own research...

Extra) And then...
Continuation of ch.1-2, a little into their future.

From Attractive Fascinante: Sensei rejected Fuji when Fuji confessed to him on graduation day. After that, Fuji always visited sensei and they still went out together. Sensei realized his feelings gradually and hoped to start afresh with Fuji. However, Fuji couldn’t believe it. But when Sensei’s ex-lover, Namiki, came back and wanted to reconcile with Sensei, both Sensei and Fuji found that they could no longer hide their own feelings anymore.

Compilation of short stories:

1) 1000 Years, I Love
Hakua is sent into the mountains by the village to kill a ferocious tiger that has been attacking villages. The tiger, mistaking him for a girl, drags Hakua into the mountains to become his mate. Love soon blossoms as Hakua must teach this half human creature the meanings of his new found emotions.

2) 1000 Years, I Love Extra
Their love going strong, Hakua decides to go back to the village. Naturally Youko tags along and runs into some trouble in the human world.

3) Lying Words Honest Kiss
A slave merchant Kouhaku steals a beautiful boy Enji to sell him to a public house. Little did he know that the boy wouldn’t mind at all.

4) Fallen Warrior
A doctor’s apprentice Suiki finds a wounded samurai in the forest and takes him to his home to treat. The samurai Genka is really bad-tempered and the boy has bad history with samurai.

5) The Flower of Love
Story about an artist Sekka and a beautiful boy Joka he saves who later comes to serve as his model.

6) The Path of Pure Love

From Tokyopop:

Masayoshi Kurozuka is an ordinary high school boy... until the day he discovers that he is the reincarnation of an evil woman named Oni-hime, who sold her soul to the devil during Japan's warring period.

Masayoshi must come to grips with his identity, all the while fighting off legions of ghosts -- the remnants of men killed by Oni-hime. In order to free himself from this curse, Masayoshi must discover the truth behind Oni-hime's deal with the devil and clear her name in the eyes of the restless spirits seeking revenge.

[From Beautiful Soup]:

"Self Portrait" is the story of a boy dating a yaoi fangirl who puts him up in a bet with an older, homosexual photographer (And he obviously loses). Hilarity and shounen-ai ensue.

DMG via Renta!

A story about the Sexual Harassment Punisher, Sakakibara, and his assistants - how they ‘punish’ those around them. Some comedy and BSDM themes, plus drama and action.

As a transfer student to a rough, run-down school populated by delinquents, Shindou tries his best to make friends. When he meets the ill-mannered Yousuke, heartbeats and tempers start to fly! It seems Yousuke is a "tsundere"--his gruff exterior hides a shy, sensitive side--and Shindou immediately finds himself dizzy over his combative new crush. Can Yousuke accept a relationship that goes against his tough-guy image? Or will his tendency to lash out at everyone around him drive even the earnest Shindou away for good?

From Viz:
Hime Kino's dream is to one day perform voice acting like her hero, Sakura Aoyama, from the Lovely Blazer anime. So getting accepted to the prestigious Hiragi Academy's voice actor department is the first step in the right direction! But on her first day of class she meets Sakura's grouchy son, Senri, who tells Hime that her voice is awful and Lovely Blazers is stupid. Hime will not let that stand unchallenged. She'll show everyone that she IS a voice-acting princess, whether they like it or not!!

Nagisa and her beautiful, intelligent best friend Yumi couldn’t be more different. Of course, her childhood friend, Ryou, is always happy to point this out whenever he can. When Yumi gets a crush on the equally intelligent and handsome Kei, Nagisa is determined to get the two of them together like any good best friend would, but it seems that Kei likes Nagisa’s outgoing personality more than Yumi’s shy one. And where does Ryou’s crush on Nagisa–and the one she may have on him–fit into all of this?