Air (katsura Yukimaru) manga

In a world after death, angels fight for their fate and their future. Yuri, the leader of the Shinda Sekai Sensen, rebels against the god who destined her to have an unreasonable life. On the other hand, Tenshi, the chairperson of the student council for the world after death, battles against the SSS members. SSS members utilize armed weaponry to battle it out against the angels harnessing supernatural powers.
The manga is, a tie-in to the anime series of the same name, telling the stories of the members of the SSS before the arrival of Otonashi in the afterlife plain.

Clannad is set in a high-school located in a Japanese town. Tomoya Okazaki is a third-year student who doesn't take his studies seriously. Always late for class, he's seen as a delinquent by the rest of his classmates who are busy preparing for their entrance examinations. Needless to say, he doesn't have too many close friends either. Tomoya seems not to mind too--until he meets a few other girls from his school. Though he doesn't care much about them at first, he soon opens his heart to them as they get to know each other better. Clannad is a romantic youth drama that's likely to be more down-to-earth than Key's other works. But like Kanon and Air, Clannad's story is expected to be another touching and heart-breaking weeper. Based off the game of the same name.

A series of 4koma comics drawn by various mangaka involving characters from the KEY visual novel Clannad. There are no game (or anime) spoilers in this book.

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 beg

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 p

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.

From Wikipedia:
Little Busters!' story revolves around the main protagonist Riki Naoe, a young male high school student. When Riki was a child, his parents died, leaving him hopeless and depressed. What saved him was a group of his friends who referred t

When Riki was a kid, his parents passed away. What saved him was a group of his friends. They called themselves the Little Busters. They took Riki out and played together with him. He really enjoyed it and his grief gradually faded away. And now, they are in the second year of the same high school. They still hang out together and enjoy their school life....

From Wikipedia:
Little Busters!' story revolves around the main protagonist Riki Naoe, a young male high school student. When Riki was a child, his parents died, leaving him hopeless and depressed. What saved him was a group of his friends who referred to themselves as the Little Busters; they took Riki out and played together with him during his time of need. He really enjoyed playing with them, and his grief gradually faded away. When the story begins, they are in their second year of the high school they attend. They still hang out together, and enjoy their school life.

The manga adaptation of Key's adult game Tomoyo After: It's a Wonderful Life. The manga is told from Tomoyo's point of view. There are four chapters.

In a world after death, angels fight for their fate and their future. Yuri, the leader of the Shinda Sekai Sensen, rebels against the god who destined her to have an unreasonable life. On the other hand, Tenshi, the chairperson of the student council for the world after death, battles against the SSS members. SSS members utilize armed weaponry to battle it out against the angels harnessing supernatural powers.

Yukito Kunisaki is a man traveling Japan in search of the "girl in the sky". Eventually he makes his way to a sleepy seaside town where he meets a strange girl named Misuzu Kamio who has dreams of flying in the sky. During his stay in the town, Yukito meets other unique people and begins to learn more about Misuzu and the town she lives in.

Plot: A series of 4koma comics drawn by various mangaka involving characters from the KEY visual novel Clannad. There are no game (or anime) spoilers in this book.

Plot: 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 a sarcastic freak? And what if it had REALLY bad artwork? Do NOT read if you don't know the original story behind Kanon.

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 a sarcastic freak? And what if it had REALLY bad artwork? Do NOT read if you don't know the original story behind Kanon.

This is the manga version of "Little Busters! Kud Wafter," the popular visual novel made by KEY that focused on Kudryavka Noumi.

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.

No summary 

Plot: Little Busters! revolves around Riki Naoe, a young male high school student. When Riki was a child, his parents died, leaving him hopeless and depressed. What saved him was a group of his friends who referred to themselves as the Little Busters; they took Riki out and played together with him during his time of need. He really enjoyed playing with them, and his grief gradually faded away. When the story begins, they are in their second year of the high school they attend. They still hang out together, and enjoy their school life.