A spin-off of Kanojo, Okarishimasu starring the adorable supporting character, Sumi Sakurasawa!

Kinoshita Kazuya is a regular college student who was just dumped by his girlfriend for another guy. Feeling down in the dumps, he decides to use an app called Diamond to hire Mizuhara Chizuru, a rental girlfriend, to make himself feel better. From their first meeting, she seems to be the perfect girl for him, but is there more to her than meets the eye? And how will their not quite typical relationship develop?

From Fate:

Mayu, a young stylist is dumped by her boyfriend, thus she needs to find a new home. She makes an aquaintance with her neighbor, Yuka Shimizu, a lonely girl with a very particular dream, to become a free-fight champion despite her small stature.

From MangaHelpers:
Haizawa is the cool kid in school. He's naturally good looking and has quick thinking. It all starts when he accidentally finds a spot on campus that lets you see up girls' skirts. First, he has a sexual encounter with the school´s most popular girl, Kuroha Ageha, after learning that her big crush is him. Next, even the young and beautiful science teacher, Ms. Shiromine, falls victim to Haizawa´s sexual aura that's starting to grow stronger.

A yuri comedy between two girls who seem different but are actually quite similar, each with a secret of her own.

Innocent country boy Oyamada Kouta transfers to a big city high school in his freshman year, and from day one, his life enters a world of crazy. First, a beautiful second-year student named Chizuru professes her love to him, then reveals that she is in fact a fox spirit. Frisky and flirty, her suggestive teasing of naive Kouta in front of his classmates embarrasses him to no end.

If that wasn’t enough, a gorgeous wolf spirit named Nozomu suddenly transfers to Kouta’s class and decides she wants the hapless country boy for herself. As fox girl and wolf girl vie for his heart, does Kouta have any say in this?

One day a 23-year-old Japanese musician travels to Mongolia in order to get inspirations for writing a piece of music. There he meets Kanon whose mother runs the "Hotel Kanon" in the desert. Kanon grew up in Mongolia, does not know who her father is and takes him for dead as her mother told her so. Then Kanon's mother who fell from a horse dies of injury. Before her death, she tells her daughter that she came to Mongolia because she could not stay in Japan as she had an affair with Kanon's father, a musician, who is actually still alive, and she asks Kanon to find him in Japan by becoming a violin virtuoso, but dies before telling her his name.
Thus Kanon goes with the young man to Japan where she learns to become a musician in a music school run by Mikami, a handsome young man and worldwide very successful musician and conductor. Soon the younger sister of her mother gives her photos of three musicians, one of whom might be her father. Kanon's erring search for her father begins.

Note: Won the Shogakukan Manga Award for Shōjo in 1997.

From Esthétique: This is a crossover between Kanon (Key) and AIR (Key). Each chapter is a separate story of Kanon (Key) or AIR (Key), they're just short mini stories that were never seen in the anime.

Taken from Anime News Network:

Changing schools is something Yuuchi is accustomed to, due to his parent's profession, and with their recent venture to Africa, he is returning to his aunt's home after 7 years. The time that has passed since his last visit has faded his memories of the people he knew, and the ties that bonded them to him, including his cousin Nayuki. Slowly those people, coincidently all being girls, find their way back to him. However, time has passed and things have happened in their own lives that sets the tone for the series. Secrets that are coming to surface, and memories that are returning to not only Yuuichi, but to those surrounding him. A very heartwarming tale that touches upon a spectrum of emotions, mystery, and the supernatural.

Collection of 4 short stories:

1) Kanon
Kanon Matsukura is a high school sophomore. Her name is based on her father's favorite classical "Kanon"... One day in school while she was walking down the hallway she hears "Kanon" being played. It was her math teacher Azume playing it on the piano awkwardly. Since then, "Kanon" keeps playing in Kanon's head. A touching story of a high school girl in love!

2) Happy Rain
Tsubasa can't confess to her basketball player Sugita directly, so she asks his teammate to pass him a present instead. Later, she takes shelter from the rain and runs into Sugita's teammate again. Can fifteen minutes in a waiting shed be enough to change one's course in life?

3) Bang!!
Shinyama sees Daiyumi holding a gun to her head and jumps down the stairs to stop her from committing suicide; but it is only a toy gun... Shinyama hurts his right hand and Daiyumi feels obliged to help him taking lesson notes. What does Shinyama feel towards Daiyumi, is it only pity or is it something else?

4) Santa is Coming
Inaba is always teasing Ayumi about not being able to get a boyfriend. In anger she lashes out that she does in fact have plans to meet a boy the next day; when she is really only baby sitting her nephew. What shall she do when she runs into Inaba taking her nephew to the game center!?

A collection of Kanon 4komas from various artists.

An alternate retelling of KEY’s classic work, Kanon, where it asks: what if Yuuichi DIDN’T lose all his memories of 7 years before? And what if he was really sarcastic? Do NOT read if you don’t know the original story behind Kanon.> Part of the Kanon series( http://www.batoto.net/search?name=Kanon&name_cond=c&artist_name=Key&artist_name_cond=c )

Kanon's story, set in the middle of winter, regards a group of five girls who are connected back to the same boy. Yuichi Aizawa, the main protagonist, had visited the city where the story takes place seven years prior to the story's beginning.

In the beginning Yuichi is very detached from the city and its inhabitants. Prior to his return, it is decided that he is to stay with his cousin, Nayuki Minase, and her mother, Akiko. After his long absence, Yuichi has forgotten almost everything except minor details of what happened seven years before and is in need of being reminded of what he left behind.

On the day after Yuichi's return, he is out with Nayuki who is showing him around town. Nayuki remembers that she has to buy things for dinner and Yuichi is reluctant to go with her, arguing that he might get lost. Moments after Nayuki left him waiting on the sidewalk, a strange girl named Ayu Tsukimiya barges into him with little warning. Upon recovering, she drags him away to a nearby café and confesses to inadvertently stealing a bag filled with taiyaki after being accidentally scared away by the salesman before she had a chance to pay. Yuichi then drags Ayu back to the salesman, they both apologize for the trouble, and Ayu is forgiven. They decide to meet up again another day and Ayu scampers off.

Yuichi is not aware at first, but three other girls which he had forgotten are familiar with him. Throughout the story, as he learns about the supernatural undertones of the town, Yuichi is reminded of each girl and the events of seven years ago in the city covered in snow.

A compilation of KANOU Miki's best works (加納みき傑作選):

1. Zenbu Agechau (ぜんぶ・あげちゃう)
2. Datte Datte Daisuki (だってだって大好き)
3. Renai ∞ Kagakushiki (レンアイ∞化学式)

A super-deformed version of Kannagi created by the original author's brother.

From HaruHime:

A perfect boyfriend that loves Kin erasers and big boobs.
A perfect girlfriend that is average-looking and flat-chested.
Cry, laugh and squeal, because this is a story of passion and unrequited love!
Although Natsu, 16, thought that Ichijou was the perfect boyfriend, it turns out it was only her illusion. When she confesses her feelings for Ichijou only to get the reply “I want a cuter girl than you,” she discovers that what he’s really interested in is Kin erasers and big boobs. Despite Natsu’s disappointment, she still finds herself being drawn to Ichijou more by the day. Where could a loving young lady possibly direct this passion of hers!?

Suwa is perfect. She has perfect grades, perfect looks and is the idol of everyone at her school. However this "perfection" has created an odd distance between her and her fellow classmates. That is except for Takeda, the boy who sits in front of her in class. It seems Takeda is the only person that is able to speak to Suwa normally and much to her chagrin he is starting to think she is not all that perfect.

From Blissful Sin:

1-4) Kanpeki na Koibito (A Perfect Lover)
The beauty, Shinohara, who just moved into the staff dorms, is misunderstood by his subordinate, Ueda, to be a masochist! Even though Shinohara tried hard to clear up all misunderstandings, his body seems to be addicted to the taunting eyes and commanding kisses, that he feels extreme exhilaration...?!

5) Then I Fell in Love (Oneshot)
Higaky Naoya, a successful crime novels writer, lives his life quietly and in seclusion in his big house all alone until he came across with an interloper.