Bae Songwoo is in a one-sided love with his longtime friend, Kim Sangjin. Living his life hiding his feelings, one day Bae Songwoo finds a suspicious book in his house, and written inside is Kim Sangjin's life story.
But Bae Songwoo is just a passing extra...?!
As he tries to ignore the book, Bae Songwoo soon realises that everything is going as written...

Ho-Kyung likes the violin, but born to a normal family, he has no intention of pursuing it as a career. When he was young, it was the small violin given to him by his friend Uiju that created the small passage connecting him to music. Now as a high school student, one accident destroys the precious violin and leads Ho-Kyung to an encounter with the violin repair workshop… A journey begins with a very simple wish, the desire to have his own violin.

After getting married, the bride suddenly sees her new husband with another woman? Their honeymoon is at stake from the start!

The gentle virtuous housewife used to be a leader of the gang?! After attacked by assassins and her husband got kidnapped, the gentle wife becomes a gangster again to defeat her enemy fiercely with bravery (to save her peaceful life with her husband).

http://www.battlecomics.co.kr/webtoons/519

From Dark Horse:

From the desert wastelands emerge two mysterious warriors, master wizard Yarong and his faithful servant Batu. On a grave mission from their king, they have yet to realize the whirlwind of political movements and secret plots which will soon engulf them and change their lives forever. When Yarong is mortally injured, Batu must fulfill a secret promise to leave Yarong's side and protect his master's child. As Batu seeks to find and hide the infant, Yarong reveals another secret to those who have tracked him down to finish him off--the deadly, hidden power of a Shaman Warrior!

* One of the best-selling manhwa epics of all time, Shaman Warrior won the Korean Culture & Content Agency's 2006 "Best Manhwa of the Year" award!

Jun-Hyun and Na-Hyun are a brother-sister duo with an almost obsessive devotion to each other. Is it simply a case of forbidden love between siblings? Or is something more sinister at play?

People start getting abducted, and find themselves in an abandoned school building with monsters when they wake up. Out of the 13 people abducted, who will be able to make it out alive? What is the exact reason behind these abductions?

Made into a free to play RPG, Lime Odyssey: The Chronicles of ORTA follows the journey of an ordinary high school student who is thrown into the fantasy world of Orta.

It's the daily life in a family...

Fairytale encounter the same village, sixteen boys and girls. One, such as one made of a piece of cloth quilt stitch, perfect love story, while not perfect.

In the world, people can be classified into three types: strong carnivores; middle carnivores and herbivores.
Somi Han is referred to as "Invisible girl". She befriends a fellow herbivore, Yujin Ko. However Somi Han feels that Yujin Ko is more like a tiger pretending to be a rabbit. Meanwhile, the entertainment industry is in an uproar with the appearance of a fanfiction writer called Foxstar. With incredibly detailed and accurate information about the personal lives of many of Korea's hottest stars, celebrities are more than nervous.
What happens when Somi and Yujin discover each other's secret identities?

From: Easy Going Scans

Yongbi is a bounty hunter without fear or reproach. Especially without fear, actually. Despite his greed and his penchant for drinking (fortunately shared by his faithful horse) and women, Yongbi is still a charming young man. And when a boy carrying a medallion, source of much envy, finds himself under the protection of the adventurer, those who cross their path must prepare for the worst!

Kim Jee-Ha comes from a good background with decent grades and test results; however, he has one big flaw - when it comes to official events like university interviews for example, he is horrible. To overcome his social awkwardness, he embarks upon the virtual reality game Trikia where he meets an eccentric high level undead Nine - his future guild master.

A couple that has been together for 3 years, but dated even less than 100 days... And, because of the playing-hard-to-get Jaehwa, Dohyung is making a fuss. Dohyung wants to do something about it, because of the naive Jaehwa, he gets really upset. However, the highschooler who lives on the 1st floor is weird. Their story is all about being foolish and clumsy in front of love.

High school boy whose heart doesn't beat meets the man that stirs up his heart.

Agne is an evil wizard who wishes for the end of the world. In order to achieve his goal, he summons a Demon King - and as he materialised from the abyss, he would proceed to end the world as Agne wished... or not. Summoned with an imperfect memory, the Demon King decides not to end the world as Agne had wished, but rather the opposite...

From etc:

“Things that should not be touched by humans somehow find their way into this world. That’s why you should never, ever touch anything that is foreign.”
Follow the adventures of March, a Syste Behard, who hunts ils– evil creatures that lurk in fascinating objects.

Among the quiet villages and towns of 18th century Europe, demons known as the Ill hide within the most beautiful works of art, sparked to life by the torment of their creators. Attracted by their jewel-like allure, the unwary find themselves possessed by the Ill and driven to horrific acts of violence. Only the hunters of the Ciste Vihad can dispel the Ill.March is one such hunter, tracking the Ill from town to town to find the antiques that contain the demons before they can possess anyone. If the worst has come to pass, March's full powers are unleashed to battle the fiendish Ill. Born of tragedy, the artifacts all have their own tales to tell, as do each of their victims. But March's story may be the most tragic of all.

When did she meet her ideal girl in the worst situation? Guk-Hwa was kissed by Jang-Mi and left. After a few days since that incident, Guk-Hwa left her work to go home, and saw Jang-Mi on the other train and tried to get off to meet her, while thinking "Why did I do that? The guy thing is already solved anyways." Jang-Mi finishes working at her place, and gets pissed off because she keeps thinking about that fight about the guy. And so she gets off work all pissed off because Guk-Hwa keeps popping up on her mind again.

Manhwa you may also like:
+ UnTOUCHable
+ Their Story
+ Jidokhage Kkeureoango Jidokhage Kiseuhago
+ My Pleasure

From Lezhin:
Hearing that his sleeping disorder can be cured by sleeping naked, Hojin decides to try it out. Little did he know that a ghost was living in his house. Little did he know that the ghost was a girl. Little did he know that the ghost was into his naked body.

A girl wakes up in a foreign world after an drowning accident and is suspected to be the 'dragon priestess'.