From MangaHelpers:
29-year-old programmer Suzuki Ichirou finds himself transported into a fantasy RPG. Within the game, he's a 15-year-old named Satou. At first he thinks he's dreaming, but his experiences seem very real. Due to his use of a 3-time-use special power (meteor shower), he ends up wiping out an army of lizardmen and becoming very high level. He hides his level and plans to live peacefully and meet new people, though developments in the game story (like the return of a demon king) might get in his way.

From Fallen Syndicate:
Sylph Anthology containing short illustrations and comics.

Part 1: Fairy Tales
Part 2: Tales of Old Japan
Part 3: Western Literature
Part 4: Japanese Literature
Part 5: Myth & Legend
Part 5.5: Special Chapter

From ADV Manga:

On the planet Aqua, a world once known as Mars, Mizunashi Akari has just made her home in the town of Neo-VENEZIA, a futuristic imitation of the ancient city of Venice. The technology of "Man Home" (formerly Earth) has not entirely reached this planet, and Akari is alone, having no contact with family or friends. Nonetheless, the town, with its charming labyrinths of rivers and canals, becomes Akari's new infatuation, along with the dream of becoming a full-fledged gondolier. Reverting to a more "primitive" lifestyle and pursuing a new trade, the character of Akari becomes both adventurous and heartwarming all at once.

From Seven Seas:
Three things you should know about Touga Eita, second-year high school student and heir to the Touga-style ninjutsu dojo: First, he really, really loves video games. Second, when given a choice between heroics and saving his own skin, he will always choose the latter. Third, he's never so much as kissed a girl.
All this changes when a voluptuous girl with wings and taloned feet named Aero appears and calls on Eita to help save her people-the harpies of Re-Verse-from the merciless onslaught of giant robot monsters known as Gigas. Eita will follow his newfound harpy friend into a whole new world, filled with monster girls and fantastical creatures beyond his wildest dreams.

This manga is deemed to be one of the works that initiated the "irrational" or "unreasonable" gag comic genre where the reason of its funniness cannot be explained by logic and traditional sense of humor, which made this title very popular among teens and early twenties at that time.

Two men chat in a prison cell about the war going on outside.

Sawatari Hu, also known as Potte, recently moved to her late father’s hometown and is restarting her life at her new school. She is typically nervous and shy but when it comes to photography, she is extremely passionate, especially since it makes her feel still connected to her dad. Hu becomes close friends with Kaoru, Norie and Maon and together, and they spend the best times of their lives together.

This is an adaptation of the OVA series from Hal Film Maker director Junichi Sato.

Windmill is another name for Kujima High School and it comes from the windmill that sits at the top of the campus. But Kujima is more known for having the strongest fighters and they pit against each other to be the top dog.

Shiiba Gaku is only a freshman but he has his eye set on beating Aramaki Itaru, aka Shake, who is the current boss of the school. But Gaku needs to get stronger if he wants a shot at the number one title.

With classmates like the big and strong afro dude Marumo Taiji, it will be do or die for Gaku at the Windmill.

From Serenus Dreamers:

Sakurai Tomo is a high -chool girl who lives in a town close to a beach. One day as she was getting molested on the bus, she gets rescued by a classmate(?!). However, the key holder dropped by her rescuer held the same Agate that she has gotten from a boy in her past?! Is he the same person?!

After his unfortunate death, Tomokui Kanata has been reincarnated as a member of the weakest race, a goblin named Rou. However, Rou has retained his previous life's memories, as well as an ability that allows him to gain strength and abilities from eating. He also possesses a unique evolutionary tree.

Now, Rou has made a promise to himself that he would live this life to the fullest. In this alternate world of survival of the fittest, events unfold with competent subordinates and comrades.

Orginal Webcomic

In a world driven by fictionalized friendship, courtesy of the program named "Real Account", the table suddenly turns, and the cybernetic world turns real! How will they survive?

This is part 2 of Real Account

Kyouko Mogami lived solely for her childhood friend Shoutaro "Shou" Fuwa. She follows Shou to Tokyo so that he may realize his dream of becoming a famous singer. When his dream is realized, Kyouko overhears the truth behind his decision to bringing her with him: he was using her as a maid.
Shocked and enraged, Kyouko swears to take revenge by outdoing him in show business. With a new look and a new attitude, she joins LME, the agency where Ren Tsuruga (Shou's rival and the #1 actor of LME) works, in the hopes of achieving her goal of destroying Shou's pride.
Along the way, she discovers her true self, makes new friends (and enemies), and finds herself at the heart of some interesting situations that will change her life, and the lives of all others involved, forever.

The second shounen-ai manga ever published, The November Gymnasium focuses on chaste, yearning love between boys at a prestigious German boys' school.

Contains Poor Mama (Kawaisou na Mama)

Hirose Goushi has a huge sister complex. So huge, he moves from his home town to Tokyo to attend Myouzen University in order to escape it!
Three years later, Goushi's little sister Noa shows up and informs him that she's taking the Myouzen University entrance exam and that she will be moving in if she passed. Little does Goushi know, she has a similarly large (if not larger) brother complex.

It features three friends, all women aged 29, who get together and socialize regularly and indulge in their common passion: drinking. Michiko Takase, the office lady heroine, prefers beer; Misono Miyauchi, a short-haired, muscular book store worker, likes sake; and Yuki Shinonome, the feminine housewife, drinks everything. The manga follows them as they visit hot springs, beer gardens, bars and more to sample different drinks, pair them with delicious side dishes, and chat about work, their family, how to keep warm while wearing skirts, etc.

In Alternative, Takeru wakes up three years after the end of Unlimited to find himself back in his room. Although he first thinks that everything that had happened to him was a dream, he soon feels that something is wrong, and leaves the house to find that he has been sent back in time to the beginning of the events in Unlimited. Unwilling to accept something like Alternative V, he decides to help professor Kouduki to complete Alternative IV and save mankind.

From Chibi Manga:

With the protection of that prediction, the days of protecting him has started!

A love comedy of the god and human who were mysteriously put together!

The story follows the adventures of a Japanese battleship, the crew of which consists solely of girls for some reason (Current submarines are actually all male crews because of privacy concerns...). This is pure fanservice and the historical details could perhaps be questioned, but as long as you like ships, tough girls and comedy, you're still gonna enjoy it.

By Fateful Encounters: After Komaki confesses and Kusame accepts unwillingly, Kusame tries to break up with her, but how?