From Shoujo Crusade:

Miyako's living her life diligently following rules, just as her deceased father wanted her to. But one day Azuma Koutarou sees her play guitar and blackmail her to join his band. How will she face it up?

There's also three extra stories that are unrelated to the main one.

Tatsuhiro moved to Tokyo to attend an art school and start his new life. In his new room, there’s a small hole in the wall. At first he can see nothing through the small hole, but one night, through the peeping hole, he saw a girl. That’s how his new life starts.

For fighting and humour fans Jo Pae, a not really sane boy, in our modern days, he wants to become emperor of Korea... His first step when he enters high school is to become the leader of the strongest school there is. No one expecting it, he actually takes down all of the school's yankees. Jo Pae is now the enemy to kill! All rival schools wants his head whatever the means!

Without doing much research on the school or surrounding areas, Hibino Ryouichiro picks an art school in Hokkaido. Tricked by the school advertisements, he goes to the campus only to find out it is a desolate and cold campus. The only glimmer of happiness for Ryouichiro are the girls on campus. Just hours after meeting Kisaragi Riho, the cute girl on campus, she seduces him only to find himself outside naked after she is done with him. Feeling heartbroken and used, he finds comfort in Aso Tomoe, who lives on the floor below at the dorms. Although it is freezing outside, it is hot underneath the sheets for Ryouichiro.

A cynical romance, 'Have you been addicted to love?'

Manga adaptation of the game Phantom Brave.

Chroma are bounty hunters for hire that deal with all manner of requests, including monster subjugation. A thirteen-year-old girl named Marona lives on Phantom Isle after losing both of her parents at a young age. Her parents had lost their lives during their jobs as Chroma and now she must become a Chroma to earn money. However, work as a Chroma is difficult and many hold her in disdain as the 'Cursed Girl' because of her ability to talk to and manipulate phantoms.

Thankfully, she's not alone since she has the help of the phantom named Ash, a friend of her parents that had died alongside them in a mission. Marona's parents' dying wish for Ash was to have him protect their daughter. Now Ash does everything he can to help defend Marona from the hardships of the world.

Rinne, a huge fan of Buddhism, was searching for a "monk-type," a boy as calm, intelligent and diligent as Lord Buddha himself, when she set her sights on a young, handsome monk-in-training, Yuuryou. She soon learns that this kid, out of his robes, is not her dream boy, but a shallow, irresponsible lady killer who goes by Yura. Is Rinne going to give up on her fantasy, or is there more to Yura than meets the eye?

An action comedy about a school for training Yakuza

From Shoujo Crusade:

1-3) Lovers in Conflict
Because of her sister who suddenly ran away, Sagiri ends up getting married in her place. Her husband is hard to understand and is a bit of an S. What will happen to their married life?!

4) Wild Rose's Crown

The sequel to the Shaman King and Shaman King Kang Zeng Bang series. Takes place 10 years after the end of Shaman King Kang Zeng Bang and focuses on the life of Hana in his teenage years.

Imagine a senpai you don't get along with. Then imagine having to work with and live in the same apartment as him! With no vacancies in the single's dorm, newbie cop, Kaitou, has no choice but to move in with his senpai from the koban, Himuro. While he's beautiful and excels at his job, Himuro has a mouth on him and he and Kaitou fight like cats and dogs. But then one morning, surprise! A sudden embrace and a kiss!

"Give me back my first kiss!" Romance, trouble and a love triangle. A fiercely tsundere senpai versus a hot-blooded rookie equals a workplace romance!

Vampires have evolved and don't rely on human blood anymore. They now co-exist secretly as normal citizens even though they are still feared and discriminated against by the society. So what happens to a female vampire trying to live a normal school life when she meets the most popular boy in school and accidentally nips his neck?

From MangaHelpers:
Before they enter high school, the boys Meguru and Shou are whining about the fact that neither of them has a girlfriend. A strange, large-breasted woman shows up, claiming that she will fix their problem, and kisses Meguru. This odd occurrence is pushed out of the boys' minds when they meet up with Souko, a friend from elementary school, who is going to be in their high school. She's grown up into a pretty young girl, and it seems like the boys might have a shot with her!
That evening, Meguru realizes that the strange kiss may have had more meaning than he thought: he's turned into a girl! He convinces Shou and his mother of his identity, but no one has any idea how to turn him back. Now he's going to have to learn how to be a girl and let go of his hope of dating his cute childhood friend Souko. What will happen to his hopes for a popular high-school life?

A story about a demon hunter named Rano who is trying to find his sister. Along the way he finds a person who has the same teeth structures as demons yet is not affected by sunlight. This person, Lessa, seems to remember who Rano is, but Rano does not remember who he is. Rano only dreams of this person; what are the connections between these two?

Three years ago, Karamura Neneko's father died. Since then, she's been living together with her older sister, Nanako. They've been living together happily until recently, when Nanako starts acting strangely. There will be nights that she doesn't sleep at home, and then one day she completely disappears. Not only that, but she quit her job at a company that she had been at for a long time.

Worried about her sister, she remembers a place that her father told her to go to if she was ever in trouble, the Raubritter. Upon arrival, she meets Shinobu and Yokana, cousins that run a detective agency, more-so as a hobby than a career. Since they are both fairly wealthy they never ask for payment. They only help young maidens in need, and since their business is a secret, only people with connections come to them. It turns out that Neneko's father helped them out a lot in the past. The cousins are heart broken to find out that he died, so they are more than willing to help Neneko find her sister.

What has happened to Neneko's sister? Will a special relationship develop between Neneko and the cousins?

During the summer when everything seemed gloomy I met Sensei and he changed my view on things. The only good trait that Azami, the bashful girl has is that she is honest and diligent. The reason why she kissed him and told him not to forget about her was because she wanted to change herself. During the new school term, the two of them meet again. This time it is at school as student and teacher...

From SCX-Scans:
Though it was a bit strange, three people ended up meeting. One, who looks younger than her age and able to see the supernatural. Another who is possessed by a "Yamanko" which refers to "Yama no ko", or a mountain child. She was possessed due to her bloodline and due to the possession, she has superhuman abilities which she can call upon. Finally, an awkward person who enjoys writing poems. Coincidentally, the three are also classmates.

Taken from the Holy Scriptures of the Old Church of Selakiel:
"When the Earth begins to perish, the Messiah will descend from the Heaven on wings of light. Clad in darkness, he will be so little yet he will be so immense surely he shall bring salvation to everyone."

"The four saints shall appear to offer him their assistance. One will give the Messiah courage, one will give the Messiah light, one will give him wings, and one will shield him from his enemies."

Note: Chapters are numbered differently starting on volume 7, since it's a beginning of a new arc

The manga is separated into 3 story arcs with close to none relation with each other's characters.
Volume 01-13: Video Girl Ai
Volume 14-15a: Video Girl Len
Volume 15b: Video Girl - Complete Story (about Video Girl Haruno)

Video Girl Ai [From Viz]:

High-school student Yota Moteuchi is so unpopular that his classmates have given him the nickname "Dateless." So it's no surprise when the love of his life, Moemi, is not interested in Yota but instead is in love with Yota's best friend, Takashi. Yota turns to a video rental shop for comfort, but little did he suspect that the shop was magical and that the cute girl on his rented tape would pop out of the television and try to fix his ruined love life!

From Aerandria Scans:
Our protagonist, Hikaru, is a member of the astronomy club at her school. On one beautiful starry night, she encounters a tall boy with blonde hair that looks almost white. However, he turns out to be...?!