A wonderful tale of a boy falling in love with his tapeworm.

Fumizuki Mai just recently moved into town and is starting her new life at school. She soon realizes that the curriculum is really weird, consisting of body fitness classes, undressing classes and extreme combat training. Mai soon realizes that her school is really a location for girls to become the most incredible women on Earth. She meets four girls who are weird but nice in their own way but their craziness and the ridiculous classes just might make Mai go crazy.

From Renzokusei Scans:

Tachibana Kazuya, Kumazawa Daigo, and Niinuma Hiroko all want to be popular. But they don't know how to do so! So, they try and create a club to research and find out how to become popular.

From MangaHelpers:
The sole survivor and witness to the serial kidnapping case that drew national attention 10 years ago was Oyamada Yusuke. In the end, a total of 108 children vanished into thin air and the case remains unsolved. Since that incident, Yusuke has been able to see evil spirits and has been attempting to seclude himself from society. But one day, he meets Kanon, a member of the anti-doll organization. She explains that the spirits that he has been seeing are called dolls and are the manifestation of people’s incredibly strong emotions. Yusuke accidentally releases a doll named Makina that even the organization had to resort to simply imprisoning instead of destroying. However, Yusuke learns that Makina has a connection to the kidnapping case that he was involved in years ago!

A boy with a special skill called invulnerability, or in other words, immortality. Hated by shinigami is visited by one! Now he and his research team have to find a way to stay "alive"

Inspired by his grandfather's skills, Kiriyama Kyoutarou's dream is to become a hairstylist. For that he enrolls in Yumemino Private Academy, also known as Tech High, the first combined technical high school in the country, more specifically he enrolls in the Beautician Department. Little did he know that his neighbor in class is Samejima Alto, an infamous female delinquent renowned for her monstrous strength. Even after that meeting his school life proves to be quite eventful as he stumbles upon a mysterious idol's secretive practice, discovers a connection with the biggest up-and-coming idol around and receives a rather unexpected request from the fearful Samejima - "Can you turn me into an idol!?". A story about following your dreams, even when everything and everyone seems to believe they're unfit considering who you are.

Rokurou, the class' cockroach (figuratively speaking), is visited at night by an alien girl who bestows magical powers upon him!
Finally, he can ascend from his status of a complete nobody to the town's unique super hero! … Right?

The story of a guy named Tokio, who's a descendant of a legendary family of youma (demon) fighters. He has the ability to freeze time because of the youma he has in his eye, Catoblepas. One day, he encounters a girl who became a target of a demon. Tokio, with his eye, will try to prevent the girl from becoming another victim of a string of mysterious events that have occured in the town as of late. Little does the girl know that Tokio is her next door neighbour.

It's about an odd girl doing odd things.

1-3. Goshimei desu!
Renjouji Kiriya holds the coveted position of the number 1 ranked host at a high-class host club "Chateau du Amour" in Tokyo. The Chateau du Amour specializes in providing the company of beautiful, cultured men to female customers. Few people know that the popular Kiriya is actually Yamada Kotarou, a boy from Nagasaki who came to Tokyo to find a way to repay his parent's debt.
Some of the other hosts, jealous of his position, are determined to get past his perfect facade to discredit him. Kiriya will have a hard time stopping them, especially after a former customer dumps an adorable 5-year-old girl on him, claiming he is the father. The only thing that could make this situation more difficult would be the arrival of his Nagasaki girlfriend Miharu, who knows nothing of his career as a host...

4. Apple!
A kind-hearted guy who grows up eating cakes and whose parents own an tartlet cafe, wants to be the ultimate gang leader. A villainous girl who was brought up in a family of gangsters wants to be the owner of a tartlet shop! How will the pair cross one another's path with their dreams of the opposite party?

In the Mazinger Otome series:

V.1 - Mazinger Otome

V.2 - Mazinger Otome Taisen

The story starts with a seemingly unassuming class rep Adachi Hana who has taken an interest in the school's known delinquent, Shinagawa Daichi. Just what is her reason for following Daichi and wanting him to go on the class field trip?

Included in volume 11 is the story called Fairy Megane, a crossover between Fairy Tail and Yanki-kun to Megane-chan.

25-year-old Haduki-san has no experience in romance but ends up being pushed into a relationship by her younger sister. Her partner is a high-school boy!? A timid love story begins.

From Viz:

Yuji has just started a new semester of high school and everything seems to be normal. That all changes when a mysterious man named Friagne begins turning people into blue flames. And wouldn't you know it? Now he's after poor Yuji!
To the rescue comes a girl named Shana. But is she too late? As it turns out, young Yuji may already be dead. What the heck is going on?

A Spinoff of Senyuu.
A story of how Ros and Alba meet.

Sumire is a 17 year old high school girl who wants nothing more than to make friends with her new classmates. She's so disappointed that they all seem to hate her, calling her a pervert, a dirty old man, creepy, weirdo... alas, what is a poor life-sized puppet to do in this cruel world.

Katsuragi Keima is known on the net as the god of getting the girls while in real life he’s known as otamegane and he hates all real girls. However he is approached by Elsie, a devil from hell, to help her in catching runaway spirits that hide in people. Apparently the spirits only hide in the hearts of girls and the only way to get the souls out is by making the girl fall in love so the spirit gets forced out. And he’s not allowed to fail or he will lose his head.

From: Easy Going Scans

Our protagonist Jo Cheul-Hee is a delinquent who enjoys picking fights and aims to take control of his new school where he gets transferred, but what he doesn't know is that it's an all girls school.
Being the only male student there, everyone thinks he is gay!

On earth's last day the survivor is a hikkikomori?

A short romance one-shot about a boy being dumped by the girl he likes, his cousin, and a cough.