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.

Becoming part of a family...

Bohm (meaning spring in Korean), on his way to give his dad, Detective Ghim, (who's been working for 10 days straight) some underpants at the police station, sees a girl by a vending machine and wishes to see her again...

Mahnsoo, a boy with a strange lonely past, the only witness to an important criminal case, must undergo a disguise as a girl and stay together with Detective Ghim's family until the investigation is over and the case ends. So he meets Bohm again, and trying to get close to his new icy brother is not easy...

When Miyagi, the head of a well-established Japanese restaurant, is confessed to by Kasuga, a chef-in-training visiting from a sister restaurant, the next day and every day after invites continuous sexual advances! Even as he struggles to resist Kasuga's proposals, what will happen as Miyagi becomes moved by Kasuga's unwavering attempts?!

From Wingtip Cafe:

Hina, Arare, and Hana are the three sisters of Kyoto’s oldest confectionery shop, Fukuya. Although they each have different personalities, they all take pride in their shop. Fukuyadou-honpo will bring you a taste of the ancient capital, Kyoto, with a shrewd mother, sharp-tongued grandpa, and a host of other characters who bring life to the great city.

1-2) Yamada runs away from home and goes to hang out at the school until things cool down. Unfortunately he runs into his homeroom teacher who takes him home.

3-5) Ikeda moves into his dormitory to find out his room mate Kazuma has a terrible personality.

The extra is about the first story.

A love story on a beautiful island far away/a tale of a castaway on a lonely island.

From NetComics:
Three extraordinary women in three age groups and three unforgettable lives intersect in Morim Kang's fascinating 10, 20, and 30. Krumb is a clumsy, scatterbrained widow in her 30's whose teenaged daughter, Rok, is forced to take care of. Meanwhile, Rok's jaded, twenty-something cousin Belle suffers a messy breakup with her boyfriend. Finally, Rok, who dreads the thought of growing up and its attendant responsibilities, hates men and is sure to complicate matters. Get ready for one wild ride with 10, 20, and 30.

English Web Publication

From Pink Rose Scans

• Ketchup Mayonnaise
Atsushi's bar-tending mom remarries to a rich, strait-laced (if not slightly old) salaryman. They move into their new house, and he can now sleep in a bed fit for a Prince! With the union, they've become one big happy family with him, his mom, his new step-dad, his step-dad's kids Peter and Kurara, and the ghost of his ex-wife....wait, what?!

• The Spring of Water
Maki should be on cloud nine---she's snagged the boyfriend of her dreams after finally confessing her love for him on the train platform, with a little help from her friend Fumika. They've even passed the half year mark in dating when everyone around them predicted they wouldn't last a month. Why is it then that she's starting to get the feeling that this was all a mistake?

• Chocolate Ice Cream
Sakura's been in love with Niiya ever since she wound up in the same class as him back in elementary school. Niiya, however, doesn't seem to be as enthusiastic about her. So of course, when God gives her the chance to change her face to one he'd madly fall for, she readily agrees! Who does she become? And does she finally get her man after 14 years of unrequited love?

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).