From Lililicious:

A series of one-shots about four sisters, each focusing on a different sister.

The first is about a good girl who is tempted to break the rules.

In the second, two girls begin a pretend relationship with each other. But when one of them actually falls in love, will her heart be broken?

The third story is about a student council president who's always late for meetings.

In the forth story, a girl has been in love with a "witch" for as long as she can remember.

In the extra chapter, Midori (from chapter 2) worries that her girlfriend has fallen out of love with her.

Anise can't believe her luck when she finds herself in the same high school as famous former child star Siva. Although the cool and handsome Siva seems unapproachable, Anise manages to become his friend. But her happiness turns to surprise when she discovers Siva's secret: for years, he's been switching identities with his twin brother, Cipher!

From acme: Dame BL is "a collection of BL oneshots written by some of the lesser-known participants in the genre (and some you may be familiar with already), with a focus on less conventional settings and characters. We're very far away from high school here, which hopefully you'll agree makes a pleasant change of pace." 1. Be Here to Love Me (KUMOTA Haruko) The relationship of a foot-fetishist and his cunning colleague. 2. Kou no Kawa (MOROZUMI Sumitomo) Set in ancient times, a village is near starvation due to a bad harvest. For some reason, the young chief takes care of a cursed man he finds lying in the river... 3. Khaa Thoong (Est Em) Can the young Thai kick-boxer rekindle the thirst for competion in a senior boxer after his devastating defeat? Column 1 (AOYAMA Toomi) Useless Side Characters Column 2 (Kashima) Obsession/Favoritism Column 3 (KUSAMA Sakae) Terror! Kappa Lake 4. Natsu no Saigo ni Yosete (UMEMATSU Machie) Two elderly men reminisce about their lives together over a bowl of peaches. 5. Locas! (OKADAYA Tetuzoh) Jean-Luc fell in love through correspondence in a chat with Al. What will occur, when he will decide to meet off-line? Is it really Al that wrote to him in chat? 6. And Robo (CHIBA Ryouko) A touching tale of robot clones... or something. 7. Shinumade BL Shindemo BL (Takeuchi Sachiko) 8. Tonari wa Nani wo Suru Hito zo (UNO Jinia) The unusual love a man has for his fan in the hot summer. 9. Soldier (Zin) A nazi sadist and a prisoner in camp. Excitement, desire, but... what about love? Attachment? Column 4 (KEVIN Komine) Column 5 (COTORINO Deathco) Eronashi BL Column 6 (PSYCHE Delico) Column 7 (YONEDA Kou) 10. Muhou no Shounen (Mochimeko) A story involving a Reckless Young Man and some scary faced gangsters. 11. Ima Doushiteru (ROTTA Ikumi) The funny relationship between a man who has a fetish for soft/chubby things and his fatty otaku-friend. 12. It Must Be (MOMOYAMA Naoko) A story about two professional cyclists and their travails.

Seung Hun is a handsome playboy who's never experienced true love. Woo Sun is a charming playgirl who wants to be loved for herself and not her beauty.

Jong Yi is the beautiful, mysteriously childlike and vacant boy who becomes the object of their affections. A complex love triangle evolves between these three, further complicated by the involvement of Jong Yi's unfailingly devoted childhood friend and first love, a girl named Yu Ri.

They're all soon to discover that love is a long, painful path...especially if the object of it is completely oblivious to your attentions!

Note: As indicated by the genre tags, there are both shounen-ai and romance pairings in this story. It is not F/M romance only.

From Go! Comi:

When her grandmother passes away, high-school student Kajitsu Toda suddenly finds two hot stepbrothers and an adorable little stepsister dropped in her lap! Kajitsu and her step-siblings have only one thing in common: they were all abandoned by their parents. Against the odds, they've pulled together to form a family without grown-ups. They don't want charity, they don't want pity... they just want their dignity!

Things are particularly tough for Kajitsu and her step-brother Natsu. As kids, they were as close as any true siblings. Now, reunited for the first time in seven years, they've grown as far apart as two people can be. Can they ever become friends again? And can two high school students living together, even as "siblings" ever escape scandal?

Detroit Metal City is about a death metal band that has gained immense popularity in the indie scene.
The main character is a push-over, Negishi Souichi, who is trying to make a living in the music world, but he didn't imagine in his wildest dreams that it would be in such a band. Read and see what hilarious situations he gets himself into.

This is a story about two girls (Yuka & Maho) who dream of becoming famous mangaka. Each chapter tells a phase in their career, starting from their first audition in a manga writing competition, until they become professional mangaka.

From MangaProject:
Imagine what it is like to be raised by a gay father who insists that you call him "mom". The main character turns out to be a woman who doubts her sexual orientation, until she meets the right guy. She is so sure that he is "the one," that she goes out of her way to pursue him and then marries him lightning fast! Essentially, the rest of the story is about keeping the chemistry (a little twisted and crazy though).

From Attractive Fascinante:

Kusaka is an owner of a used-book store and is oblivious to the people around him. Iijima, on the other hand, is a hotheaded sales person. They were classmates during college and had some argument before, yet they became lovers now. When two total opposites personalities clash, the spark of love starts to disperse too…

Note: Chapters 7-9 were NOT included in the licensed volume.

Doujin Market. It is a place where individuals sell their self-published books. Each participant works daily to achieve their personal goals.

While their are some who obtain their dreams, there are also those who get pounded by reality. This is the story of those who live in the world of Doujin.

Izumi, a young art student goes to visit her old professor who is living out in the country. Izumi is trying to get away from something and wants to take a break at the professor's house for a while. When she stumbles on Sensei's secret sexual fetish, it sets off a tense relationship full of awkward moments and weird demands.

From Fantasyshrine:

Usami is a chef of an Italian restaurant called MIYA. One day, the whimsical owner decided to turn her restaurant into a "bishies restaurant"! Usami refuses to be part of this frivolous idea and will do anything to get out of it. Which led him to strike a deal with the owner. So now he’s stuck training Komiya, the spoiled, playboy son of the owner, to take over the business. But Komiya decided to make a deal of his own—!

Childhood friends Chihiro and Keigo are living together under one roof. They're lovers, but they've only ever kissed once. To Chihiro, it hardly even feels like they're going out, and he's getting impatient! And on top of that, he suddenly has a rival!? It's ever-loyal Keigo and headstrong Chihiro's heart-pounding, heart-breaking LOVE!!

-DMG

Diotima is set in 2092, far in the future. This manhwa is considered sci-fi for that. However, the manhwa's plot is "life". The episodes involve lives of captain Namer Joon and her crew onboard the space vessel, Diotima. The plot goes a little further and tries to convey conflicts between Earthians and Moon settlers. There are clearly some mysteries about Namer Joon, Diotima, and its creators.

Jr. high student Izumiya is surprised by a sudden kiss from his handsome classmate Hayakawa. Leaving him completely confused, Hayakawa suddenly leaves town, but the two reunite again in high school. As the two continue to part and reunite, Izumiya's feelings start to stir...

From SCX-Scans:

It tells the story of a couple, both very innocent and in love with each other, who are now living together! Takeshi is a pure-hearted college student who is enticed by his girlfriend that has run away to live with him. Temptations ensue.

From JShoujo Scans:

With the ability to see the negative emotions of people, and to see it as if they’re monsters, whose character can be different and weird, she is Deng. Because no one can understand how she feels, a wall has been built around her heart. However, after living with her innocent brother and with the help with some good friends and Karas, the person that can consume evil intensions, her world has begun to change…

Just before entering the university, Yanagiba Masahiko's father died in a car accident. His mother died when he was four, which makes him now really an orphan. But even before the death of his father, he didn't have a family life, as his father was always busy or abroad.

When his mother's younger brother and his wife decide to invite him to live with their family, his life takes a turn. But it is not going to be the normal family life he is imagining for himself. What is the "terrible" secret that led his parents to break the bonds with his aunt and uncle? What could be the true nature of his cousin, Shion? And last but not least, will this "terrible" secret eventually get Yanagiba, too?

From Dragon Voice Project:
Family Complex... This is exactly what Akira Sakamoto suffers from, being the second eldest son of the Sakamoto family and the only NORMAL person. The rest of the family consists of beauties, from the parents to the eldest son and the 2 daughters. Poor Akira feels that he's totally out of place, and tries to hide this from the others... but then one day it all comes out. How will his family react to this? In this hilarious manga, every chapter is dedicated to one family member, starting with Akira. Family Complex isn't quite like anything else.

The second eldest son, Akira. Appears in another manga Princess Princess as a minor character.

Anji is the complete opposite of her beautiful, smart and ambitious older sister Anri. To make matters worse, Anji has a hopeless crush on Anri's boyfriend Baek-hui, who is her sister's match in looks, brains, manners and goals. But is Baek-hui all that he seems? From Baka-Updates: Anri and Anji are sisters. Anri is one year older than Anji. Anri is a person with determination and guts, not to mention top grades and attitude. Anji has really nothing to offer. She can be quite mean and unreasonable. But, when it comes down to her sibling, she can be pretty determined. This story details the troubles that Anji goes through because of Anri's two-faced boyfriend, Baek-Hui Kang.