An ever changing (and unusual) love triangle story, set in modern Japan.

[From Lililicious]:
Uchida is in love with Nakano, but feels like she can't tell him because she turned him down when he confessed his feelings to her years ago. One day, she sees him with another girl-- Kobayashi. The three begin spending time together, Uchida wondering all the while if Kobayashi is in love with Nakano and vice versa. It isn't until much later that she finds out the true object of Kobayashi's affections...

Abandoned in a dojo with orphans from a war-torn country, The Story of a boy called Nitro Begins where being strong in the world "Koryoku's" can be good or bad. Koryoku's(potency) are Debris formed from the age of Dinosaurs and from an unknown meteor that made that period extinct granted power to these rocks. Nitro hoping to form a team with his former classmates will now have to form a new team to help him become the World's Dictator(the strongest Koryoku user on the planet) and make a law that will avenge his Teacher, But can he achieve this evil goal with his good natured heart, A bone koryoku that grants Nitro "Eternal Bones", Other koryoku users that aim's to be a world dictator themselves, And funny circumstances that stands in his way! This adventure's starting line is Here!

From Aerandria Scans:

Tomita Yuri has hated boys since she was little, seeing them as the devils who taunt and tease her. So when her all-girl school Kinka academy decides to merge with the Ginka academy for boys, her ‘heaven’ is once again threatened by the devils from hell = men. Not only that, but being a member of the student council, she now has to work alongside the male student council of Ginka academy. Will Yuri’s ‘heaven’ be overrun by the male devils from hell?

SynopsisHitomi Nakamura, a recent high school graduate, moves in with her childhood best friend, Tomoko Obata. During the course of their living together, they both grow closer and fall in love, combating disapproval from family, self doubt, and Hitomi’s abusive ex-boyfriend. Can love survive in the face of overwhelming adversity and the trials of life? Only time will tell…

"No matter how much you like me, I'll never fall in love with you!" Takanshi Satomi was confessed to her superior Kurokawa, however she bluntly refuses. She hates to be tied down, and rather be partying and having non-serious relationships with guys. However, being forced to work overtime by him, she starts to find his persistence rather cute. Can she fall in love with him and finally settle down?

This is a manga adaptation of the Italian comic series of the same name.
Five girls find out they are the new guardians of the elements earth, fire, water, air and energy. Will Vandom, Irma Lair, Taranee Cook, Cornelia Hale and Hay Lin fight against the monsters from the parallel world called Metamoor and their evil prince Phobos.

Short stories about dog and its owner.

In the Tengoku no Inu Monogatari series:

V.1 - Tengoku no Inu Monogatari
V.2 - Zoku Tengoku no Inu Monogatari
V.3 - Shin Tengoku no Inu Monogatari
V.4 - Kiseki
V.5 - Negai
V.6 - Zutto, Zutto Issho ni
V.7 - Last Letter

This was actually created as a promo for a movie by the same name(Heaven's Bookstore). http://www.imdb.com/title/tt0423360/Satoshi-kun, a drifter, arrives in heaven to work at a bookstore as a substitute manager. There he meets Rui, a girl who also temporarily works there. Follow the daily events of these two people as the place they are in (Heaven's Bookstore) help those regain what they lost.

Hiroyuki is a student on a scholarship to an elite school for the rich. Being the only normal kid there, all of the other students treat him pretty badly. But his life changes forever on the day he accidentally collides with the rich and beautiful Saionji Haruka.

After a lot of violence and an accidental kiss from the angry Haruka, a bewildered Hiroyuki finds himself married to her! As for Haruka, by the end of the day she's lost her home, her fortune, and her family, and only has one lousy, poor, "husband" (Hiroyuki) to show for it. Will the two of them be able to adapt to their life together, or will they kill each other first?!

Gift From Heaven
Hikari befriends a gentle boy named Seiji who suffers from a weak heart while she was hospitalized. She begins to fall for Tsukina, Seiji's twin brother, who has always sacrificed for his sick brother. Tsukina believes that Seiji is in love with Hikari and steps back from the two, much to Hikari's dismay. What will happen to the three?

Reflect Me in Your Eyes
Karo is in love with her childhood friend Tetsuro, but he seems to be in love with her older sister, Touko. One day, Tetsuro injures his eyes and Karo pretends to be her sister to make him happy. Will she be able to tell him the truth, or are things not as what they seem?

Full-Point Kiss
Meru (14) has a big crush on her tutor, Yuuri (19). She repeatedly fails her tests, and makes a deal with him - if she manages to get 100 on her test, he'll kiss her. Will she succeed?

I'm Head-Over Heels In Love With You
On his first day of being in Osaka for university, Yuusuke is mistaken for a pervert after an attempt to save a woman called Suzuran on the train. To make up for it, Suzuran invites him over for a meal and they end up having a one-night stand. Yuusuke finds himself falling for Suzuran's bubbly and straightforward personality, but what are her real intentions? Is she just playing around with him?

Gift From Heaven Extra
Seiji's real intentions are revealed in this 16-page extra

The love story of a 20 year old. Original Webtoon http://comic.naver.com/webtoon/list.nhn?titleId=671270

Torte, a little witch girl, comes to Earth to complete her training and find her master, and for that she picks an employee of Famitsu (the famous video game magazine this manga was originally serialized in). Thus begins the witch's life at Famitsu.

She has looked up to her senpai on the basketball team for a long time. Now she finally makes her move as the biggest game of the season approaches.

Ran is a bright and energetic first year junior high school student who possesses supernatual abilities. Together with Midori (A troubled girl who posesses similar abilities) and her childhood friend Rui, the threesome are constantly embroiled in mysterious circumstances. Ran and Midori must learn to deal with their abilities and the prejudice and fear of those people who refuse to accept them because of it.

The manga follows the life of Minagawa Nobara, a first year in high school. After having lived on the countryside her entire life she finally gets to go to the city for high school where she is reunited with Shuwa Ibuki. Minagawa met Ibuki five years ago at a party his grandfather had organized. There he had helped her when she was being bullied and the two of them became friends. Now, five years later Minagawa meets Ibuki again but doesn't feel like she had known the real him at all back them. Or did she?.....

From the manga habit:

A gruff, loner office worker has dreams where he’s part of a team that takes orders from an eccentric leader. They’re given odd tasks such as dirtying the laundry or stealing pudding from the opposing team. Initially annoyed, the older guy begins to enjoy the dreams after an adorable high school boy on the other team worms his way into his heart. Turns out, the others are people who exist in real life and share these dreams–so does he have the guts to meet the cute boy in person?

Collection of 5 oneshots: ティーンズブルース (Teen Blues / Tiinzu Buruusu) 空色NO.青 (Sora Iro NO. Aoi) ゴキゲンだぜ! (Gokigen da ze!) 空に咲く花 (Sora ni Saku Hana) 愛の▼愛のしるし(Ai no Ai no Shirushi)

From Yaoi Is Life:
Passionate bird shop owner Masaka Toru meets foreign exchange student Fon-kun, who now makes regular visits to the shop. What is Masaka to do when he receives an unexpected confession from his regular? And what is Fon-kun to do with a parakeet as his love rival?

Four murders have taken place at an all girl school. Lying beside each of the victim was a teddy bear with one missing limb. Now It is up to Detective Hebizuka Amaru and his cute assistant Kohijiri-kun to solve the mystery!