From Beyond the Sky:

Akatsuki and his good friend Kiyoharu (whom Akatsuki calls Kiyo-chan) have been playing one-on-one basketball for quite sometime. Unfortunately, things started to change after they joined a very strong basketball team in their new school. Both of them were forced to separate into two groups: Kiyoharu was in the "B" group, and poor Akatsuki was put under "F" group, which is known as the "Failure" group. However, Akatsuki was not discouraged at all. He continues to train hard and always has a smile on his face. Will Akatsuki succeed in his promise to Kiyoharu to become an official player? And what is blocking the path to his goal?

From Tokyopop:
Aliens have landed on Earth and are now a normal part of society. These beautiful beings have been given the name "DearS" and are trusted and welcomed by most humans. In order for the "DearS" to learn Earth's customs, they are sent to random high schools to "home-stay." When Takeya helps a DearS in his school, she calls him "Master." Thus begins the humorous life of Takeya and his sexy alien follower, Ren, who tries to figure out the wacky customs of this place called Earth!

In the near future, human technology becomes centered around Mystickers, or tattoo-like stickers which are placed on objects in order to use their abilities. But Mystickers can do much more than this, a secret only "Blazers" know. A secret Daichi, a good-humored teenager with an obsession for all things "cool," is destined to find out when he suddenly finds himself targeted by people who tell him he, too, is a Blazer...

Futakoi Alternative tells the story of Rentarō Futaba and his detective agency. One day a set of twins, Sara and Sōju, show up at his doorstep. They move in with him and work as secretaries for his agency.

From Wikipedia:

Shimeru Futaba is a normal high schooler living a normal life, active in his school's wrestling club and slowly getting closer to his awkward love interest, Misaki. This fails to last, as he discovers his family's hereditary genetic defect that becomes active at adolescence. Although it will eventually become controllable, excitement and stress now make Futaba switch sex. Hilarity ensues.

Following the Tuatha de Danaan's seajacking incident, things are back to normal at Jindai High School in Tokyo, or as normal as they get with Sousuke guarding Kaname. After finding out who betrayed Mithril and caused the seajacking incident, Kurz and Mao are sent on a top secret mission in order to capture and bring the traitor back.

However, Sousuke and Kaname's lives are about to change when they meet Leonard Testarossa, a high ranking member of a mysterious group named Amalgam. After their meeting, Leonard warns her that he would do anything to recruit her even if it means war in the streets of Tokyo.

From ADV:

Trouble always seems to follow the beautiful and sassy, Kaname Chidori. Though she is only a high-school student, Kaname is constantly the target of terrorism. Lucky for her though, the dreamy Sosuke, an undercover agent from Mithril, is one step behind her, ready to protect her at any cost. But will he be able to save her from harm every time she is in trouble?

Fifteen-year-old Otawa Ryuuichi decides to train in karate after being dumped by a girl who only liked strong guys.

While testing his 8 mm camera at night in his small town, Kaito Kirishima is caught in a mysterious explosion. Strangely, Kaito wakes up the next day perfectly fine, but with no recollection of what exactly happened the day before. Unfazed by what seems to have been just a dream, he heads to school not giving much thought to the incident. Discussing his camera with his friends, they decide to make a movie during summer break. They invite two upperclassmen to participate in the project: the recently arrived Ichika Takatsuki and the odd Remon Yamano. In a strange twist of fate, Ichika starts living with Kaito because his sister has to work overseas. Summer days are about to get exciting for the small film crew.

From Village Idiot:
What will happen to an ordinary human teacher who falls into a youkai school, with his only ally(?) a sexy but air-headed nekomata? A slight ecchi and heartwarming read brought to you by the author of “Sore wa Totsuzen, Unmei no Aite ga”

A short story about a cat demon and a teacher.

From: Easy Going Scans

Ju Ingong (which literally translates to Main character) has been terrifying all his schoolmates in every school he has been so far. He has one extremely scary face type and whoever lays his eyes on him thinks he is a BAMF (bad ass). Although… is he really?

From Easy Going Scans:

Piano prodigy Arima Kosei dominated the competition and all child musicians knew his name. But after his mother, who was also his instructor, passed away, he had a mental breakdown while performing at a recital that resulted in him no longer being able to hear the sound of his piano even though his hearing was perfectly fine. Even two years later, Kosei hasn’t touched the piano and views the world in monotone, and without any flair or color. He was content at living out his life with his good friends Tsubaki and Watari until, one day, a girl changed everything. Miyazono Kaori is a pretty, free spirited violinist whose playing style reflects her personality. Kaori helps Kosei return to the music world and show that it should be free and mold breaking unlike the structured and rigid style Kosei was used to.

Won the Kodansha Manga Award for Shounen in 2013.

Reiji and Kasuga head out to Tokyo to become the "Gods of Rock," but they seem to always attract trouble. On their way, Hayama Ryo and Fujii Ran join them in their quest.

Welcome to Cromartie High—a melting pot of underachievers and overzealous bullies, where the fist rules, and the student body has the combined I.Q. of a rusty nail. After a whole lot of bad judgment and a little bad luck, Takashi Kamiyama is now attending this academy of dunces. Here, his only homework will be defending himself against the foul-mouthed robots, semi-intelligent apes, and masked villains that roam the halls of Cromartie High School!

Won the 26th Kodansha Manga Award for Best Shounen in 2002 (shared with Beck).

Note: The chapters are incorrectly numbered starting from Volume 14 (the volume begins with chapter 267 even though the last chapter of Volume 13 is 269).

Ishiyama High is a school populated entirely by delinquents, where nonstop violence and lawlessness are the norm. However, there is one universally acknowledged rule—don't cross first year student Tatsumi Oga, Ishiyama's most vicious fighter.

One day, Oga is by a riverbed when he encounters a man floating down the river. After being retrieved by Oga, the man splits down the middle to reveal a baby, which crawls onto Oga's back and immediately forms an attachment to him. Though he doesn't know it yet, this baby is named Kaiser de Emperana Beelzebub IV, or "Baby Beel" for short—the son of the Demon Lord!

As if finding the future Lord of the Underworld isn't enough, Oga is also confronted by Hildegard, Beel's demon maid who insists he take responsibility as Beel's guardian. Together they attempt to raise Baby Beel—although surrounded by juvenile delinquents and demonic powers, the two of them may be in for more of a challenge than they can imagine.

Morinonaka Iyo is a shut-in (hikikomori) who refuses to go to school, choosing instead to coop herself up at home all day surfing the net and browsing online auctions. However, her homeroom teacher will stop at nothing to make her go to school...

One day a tanuki named Monoko stumbles across a baby abandoned by its mother. Having no family of her own, she raises the baby to the best of her ability even though they originate from different species. Hardships and enemies face the tanuki but that doesn't stop Monoko protecting the baby at all costs. Many trials await this baby as it grows and communicates with the animal world.

Won the Kodansha Manga Award for Children's Manga in 2013.

Yoshimatsu Hotaka is the president of the manga club and is always diligent with his studies and club responsibilities, even though he has a habit of skipping class activities. Although he looks like a regular honor student in reality he is overwhelmed by melancholy and haunted by his past misfortunes. Meanwhile, he makes sure to admire and watch Awaya Nika, the beautiful, bright, radiant, super cheerful swimming club's female ace. He's content to continue his high-school days like this until the P.E. teacher makes him take a private swimming lesson to make up for all the other lessons he had missed; a development that would forever change the dynamic between him and Awaya. What's the cause of Hotaka's bitterness? What does he want to hide?
How does Awaya Nika have more in common with him than he could ever imagine?

Kyousuke wants to be a cop. Because of that, he always tries to do the right thing and help others out. Well, while saving a girl from some bullies, they end up liking each other. Not to soon after, she needs saving again, and he ends up with woman's panties over his head, giving him super strength (pumped with horniness.) Not your normal super hero.

Take Isamu is the best at everything he does at school, from looks and smarts, to his luck with girls and his abilities as an athlete. He considers himself to be in the top percent of his age group and is incredibly bored with interacting with the so called "normal people". That is until a new student, Kaname Moka, transfers into his school and, as she is quite pretty, Isamu asks her out. Moka mishears what he says and thinks he wants to challenge her to a fight, as she grew up on boxing. Determined to win her heart, Isamu decides to become a great boxer, with the help of new friends and allies he and Moka meet along the way.