From: Easy Going Scans:

Long ago, when danger approached the Earth, there existed people exhibiting their superhuman powers to save the planet; to help the weak; to defeat evil and to promote justice. Earth never hesitated to sacrifice such beings.

The powerless set these people apart and honored them by calling them heroes. However...the era somehow changed...

Hardworking level one magician Konoha is apprenticed to lazy Knight Protector Saionji Ikumaru. They both work to keep the ether world sealed away from their own but sometimes the seal doesn't work. Dragons, demons, and now Ishtar, the goddess of Venus. Will Ishtar help Konoha win her master's affections? Or will she take him for herself?

Utsuru Sanada is a professional photographer at the age of 17, he can guess the exact 3 sizes of any girl, he can memorize anything he sees, and he can counterattack karate moves (most guys would want these abilities). Why? Because he has superb photographic memory called “Shutter Eye”. He meets Niko Kurihara, the female protagonist, who dislikes men, is a master of martial arts, and is of course beautiful. Utsuru attempts to prove to Niko that he is not the guy she thinks he is so that he can take a picture of her. He starts by investigating Niko’s friend’s date, who appears to be a deceptive guy according to rumors…

Ran as a one-shot in 2009; started serialization in 2010.

Saiki Takaya, a guy who is easily misunderstood, one day finds a flask containing the succubus Lilim. She is very attractive but, she also has the tendency to drain the life force out of people. She surprises the life out of him (literally) when she kisses him unconscious. Lilim then flies off for more "food," but returns later, saying that Takaya's life-energy was the "tastiest." From then, Lilim is accepted by Takaya's parents as a live-in girlfriend of sorts, and Takaya's heart seems to start wavering towards this voluptuous devil.

Daisuke is a 23 year-old new schoolteacher. He ends up being put in charge of a 3rd grade elementary school class since the previous teacher quit, and in that class there's a girl who's quite a troublemaker--Rin Kokonoe. You could call her a masegaki (used to describe a kid that acts more like an adult in some ways), and she's also part tsundere (though more dere than tsun).

Rinne Ikaruga is just your average 16 year old girl, trying her best to get by. One day, she receives a package addressed from her sister, inside of which is a little girl who just happens to be part planarian and can multiply.
A planarian is a kind of non-parasitic flatworm organism.

From Taruby:

Our protagonist, Moji Shimeta, just so happens to fulfill the stereotype for being a worthless human. His inability to carry out a conversation has left him at the bottom of the barrel as far as friends are concerned.
That Shimeta fell in love with the school idol Ishikawa Yuuko, however that kind of love is absolutely, perfectly, and completely impossible. During this time, the messenger of the gods, Osaki, appeared to grant Moji's request with a price attached concerning Moji's cooperation in catching some runaway evil spirits. However to catch them all, Osaki uses Moji as a vessel to become a servent of Uganomitamanokami (aka Inari) called Youko. Lots of Ecchi situations and humiliation abound at Moji's expense.

This is a story about 2 childhood friends, Masato and Yuki, that reunite as teenagers. Masato is surprised to find that Yuki has become so cute, but even more surprised to realize that Yuki was, and still is, a guy. Yuki's affection for cross-dressing leaves Masato with feelings of discomfort and fright.

Matsuri Ichimatsu, Haruno Koume, and Sanguubashi Takezou are old friends with one thing in common: despite their good looks, they're incredibly unpopular with the ladies. But what does Polaris have to do with their fate? And will they ever get that harem they've always wanted?

One night in the Windbloom Kingdom, Princess Mashiro Blan de Windbloom is assassinated in her sleep. Some days later, the main character, an anonymous boy, arrives in Wind City, capital of Windbloom. Using a gem passed down from his mother, he takes up the identity of Mashiro and joins Garderobe. The story follows his experiences in Garderobe and later his battles against those who would seek to destabilise the peace.

One rainy night, Wada, a young teenage boy, standing near the edge of a bridge over a raging river - is on a depressing brink towards committing suicide. Suddenly, a beautiful blonde foreign girl, named Lisa, mysteriously appears. Who is this cheerful girl? And why is she dressed as a cheerleader? Wada wasn't interested and tries to ignore her, but Lisa kicks him off the bridge, and says "try flying." And to his surprise, he does. This power, where did it come from?

It seems that there is a war between the gods and demons. And by fate, the result of this war is tied to Wada. Upon learning this, Wada does not look very pleased. Was this his purpose - his destiny? What will he choose? Does he even have a choice? Afterall, Lisa, the goddess cheering him on, is surprisingly his classmate.

Iroha, a masculine girl, and Hifumi, a feminine boy, are siblings who have transferred to a different middle school and moved to their grandparents house. However, after the first night, much to their surprise... they've switched genders. The two are left feeling "delighted"...

Weak, bullied, and pessimistic about life, that's Setsuna Kashiwagi. On the verge of jumping off a bridge, a mysterious man appears behind him and offers the contract "10 million yen in exchange for your life in a year." Skeptical at first, he accepts. Waking up the next morning, thinking it was just a dream, he notices 2 beautiful women sitting beside him. They are Kanna and Rena, Oni princesses here to claim his heart in a year.

Sequel of Beach Stars, the story begins where it stopped in the first one.
Nanase, who's now the representative of her prefecture, has finally joined the Madonna Cup and will do everything in her power to defeat her one and only target: Hayakawa Sanae!

With his phrase "don't you dare make girls cry," Makoto Tobita has failed his 30th confession, but that won't stop him. Promising to do anything for the girl who smiles at him, no matter what it is, what will happen now when the alien fighting - giant girl, Mana Eimiya, is in love with him?

Furoku is a Shinigami who fell in love with a girl, Himeka, while waiting 6 months for an old man to die in the hospital. The problem is, she is supposed to die in heart surgery, and not only that, she's meant to go to hell. The reason being, she was born with a weak body, but dreams of taking over the world if she had a stronger body. So, Furoku offers some of his life up to save this "girl who hasn't done anything wrong". What future lies ahead of Fukuro and this "Bloody Queen"?

Shino asks his best friend Akira to help set him up with Maruyama, the girl of his dreams. Unfortunately, Akira ends up taking her for himself.

Depressed, Shino heads down to a black tea shop run by a guy named Shuuji to drown his sorrow by pigging out on cakes. Sometime in the past, Shuuji had a spat with a friend or something (referred to only as “that guy”) who thinks the best way to make up is send mysterious unmarked packages of randomly selected tea. I guess he has a history of sending dangerous gifts, as Shuuji gives Shino the tea “on the house” to see if it’s poisoned. Well, the tea appears to have been laced with a genie, who promptly grants Shino his desire to be with Maruyama… But be careful of what you wish for…

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From Taruby:
This tale begins with Shino who was in love with a girl called Maruyama. Shino asked his best friend, Akira, to set him up with Maruyama, but instead Akira betrayed Shino. Depressed, Shino goes to spend the rest of his day binging on cakes at the Seijou Black Tea House which is run by two mental cases by the names of Shuuji and Keisuke. Mix a magical tea leaf, homosexuals, and various other things for ensuing hilarity.

「 Don't Interfere with My Life!! 」

Handsome face and all around sportsman, also the young master of an enormous rich family...Chung-sol High school's No. 1 Han Sang-Ah!! This young master who doesn't lack anything ventures running away from home?! Officially permitted runaway time is 3 years! During this time there is something he says he must get in his hands...!! From then on starting to confront him are woman!! woman!! women!!!

Harem Flood Mixed with Comedy and Action! Explosion of Heart Fluttering Pink that would tail all Korea's Bookstores!!

(Source: volume one's backcover)

Senguu Fumihiro is a young boy that made a promise to his dying grandmother to find a good wife for himself. With this intention he enrolls in a prestigious school but on the first day his world turns upside down when all the students begin to kill each other and one of them even turns into a monster. He is saved by a girl named "Akari" sent by one of the factions that rule the school to protect him. From Baka Updates

Kaname Okiura, a student of Prefectoral Umineko Shougyou High ("Umisho" for short), joined the school's swimming club in order to learn how to swim, but the club is filled with weirdos, let alone teaches him swimming. Then, a sunny, happy-go-lucky girl named Amuro Ninagawa who was transferred from Okinawa joined the club. Her extraordinary underwater speed and unorthodox swimming style (plus her personal habit of nude swimming—a powerful magnet to teenage boys) surprised every club member, especially Okiura, because she reminds him of a mermaid-like creature he saw only once in his early childhood.