From Hoshikuzuu Scans:

Detective Hishima’s lover is former colleague and detective, Enokizu. He is still sore over an unresolved incident that occurred 3 years ago that caused Enokizu to quit his job as a detective. The story of heart-throbbing, imperfect love.

From Easy Going Scans:
The fourth son of the famous Caluanthes family is, well, quite infamous. Mockingly referred to as a bird of paradise, Force dresses gaudily, spends money like water, and has turned the trip he's been sent on to learn more about the world into his own personal gourmet dining tour. His behavior makes the rest of high society whisper about him behind his back. The only exception is Eiri Lawrence, who finds Force and his entourage intriguing rather than laughable - and who is everything that Force is not. Theirs is the world of high society, where truth and falsehood, and dark and light, intertwine.

The manga adaptation of the latest RPG in the Persona series from ATLUS: Persona Q: Shadow of the Labyrinth. One stormy autumn night, the P3 gang is bummed that Gekkoukan High School's Culture Festival was canceled due to the weather. But out of nowhere, they hear a bell begin to ring. The next thing they know...

Dio is a rock vocalist that got stuck in a battle against the Hell Princes on Earth. In between his glamorous rock & roll life, his pop idol "sister", and being chased by his bitter past, he has to fight the creatures from hell that are trying to kill as many human as possible. This is a start of a Rock and Roll Action Series!

From Nagareboshi Manga:

Kitazono Meiko falls asleep in the library one day, only to be awakened by a kiss! She is unsure of who it was that kissed her, however, since there are multiple boys still in the library. Could it be the popular boy Shinoda-senpai? Or the super-cool Mikoshiba-senpai? The boy-next-door type Mogami? Or the cute underclassman Hachiya? Who could it be? They're all possible candidates, but which one does Meiko like the best...?

Oneshot in volume 1:
Soprano (released by Ouiratsuike)

Oneshots in volume 2:
Anna no kami ga nagai riyuu (released by Sound of Jewels)
Hakka drops (released by Sound of Jewels)

Retired soldier Araki Kyosuke returns to Japan to settle down for a quiet life but when he meets heir to a big corporation Mimasaka Lune, old memories of a former life flash into his mind. Reluctantly, he becomes Lune's bodyguard to protect his protégé from attacks while learning of their past lives.

Redix and Kai lived a simple life , but suddenly and for unknown reasons , they started some commits for riot in the region . Currently they are studying the last year of High school , So they decided to stop those works for the purpose of finishing school, However .. One day they escaped from school just for fun and playing around ! But suddenly for strange reasons they found themselves in another world seemingly devastating and empty of its inhabitants ,but who knows if there are other people in this world or not ? and why were they transferred to it ?

At age 33, I am a loser, jobless and virgin, who only has remorse and pity for myself. Called by Anna, my secret crush in my childhood, and her fiance, I come to face the reality. But after I fall from the roof (caught wearing a grade school girl's swimsuit) I find myself to be back in the past. Now I will get my life back.

This is a continuation of the Durarara!! manga starting with the Akane Arc.

A serial killer is on the loose and authorities are baffled! What they do not know is that this case requires non-traditional research methods. That's where Mako Miyoshi the detective and Kyosuke Kagami the Shikigami user enter the picture. Together they investigate supernatural crimes!

"How would you save someone when you're imprisoned?" "How would you fight for justice, if you need to break the law?" "Rui Takahashi, the protagonist found a way to solve this and tries to fix all the mysteries in his life" This is a Philippine-Based Manga :)

During their school days, Rin and Karaku were a detective duo of sorts. One day they meet again as adults, and indulge in a stroll down memory lane together. But what one of them doesn't know is that he is already dead, wandering the earth as a ghost...

From Viz:

After orphan Teru Kurebayashi loses her beloved older brother, she finds solace in the messages she exchanges with Daisy, an enigmatic figure who can only be reached through the cell phone her brother left her. Meanwhile, Teru meets and forms a strange friendship with mysterious Tasuku Kurosaki, her school's janitor. For some reason, Kurosaki always seems to be around whenever Teru needs help which leads Teru to wonder: Could Daisy be a lot closer than she thinks?

As the mystery of Daisy unfolds, Teru also discovers that there may have been a lot more to the life and death of her brother than she ever dreamed . . . and that the man she thought was her friend just might have all the answers.

From Kirei Cake:

The colourful story of Aya, Hina, Kei, and their classmates, trying to figure out the mystery behind Risa's sudden disappearance. It all begins with the discovery that her disappearance has some correlation to the online dating site called "Amore." Hina proposes that they should try out the site first-hand themselves, and upon doing so, they encounter something completely unexpected?!

Based on the game of the same name.

From MangaHelpers:
In the 1950s, an old woman was brutally murdered on the face of a clock tower by her adopted daughter. Two years later, the clock tower is known as the 'ghost tower' and it is supposedly haunted. Through an unusual series of events, a young NEET man named Amano Taichi is attacked by someone or something in the same clock tower, and finds himself bound to the clock face to be killed in the same way as the old woman. Luckily for Amano, he doesn't meet the same fate. He's rescued by a mysterious person who claims his name is Tetsuo. He is searching for a treasure that is connected with the ghost tower, and he wants Taichi to be his partner. Taichi, whose life has mostly consisted of poverty, loneliness, and pornography, is enticed by the idea of gaining extreme wealth. He's further convinced when a house fire leaves him without a home and depends on Tetsuo's charity. The adventure is going to be very dangerous, since the same 'enemies' who attacked Taichi before seem certain to try something again! Not to mention, Taichi really knows very little about his new partner.

Oogami is a detective by day and exorcist by night, solving cases and hunting spirits together with his ghostly assistant Kazari. One day, a mysterious package with horrifying contents arrives in Oogami's mail, the only clue to its sender being the name of a remote village: Shirasunamura.

Billy Bat is a comic-in-a-comic and the real protagonist is a Japanese-American artist named Kevin Yamagata who draws Billy Bat for "Marble Comics".
Shortly after they transition to the artist in his studio with his assistant, two actual detectives, who look like Laurel and Hardy in Dick Tracy era suits and trench coats, knock on the door and appropriate Kevin's room for the purpose of conducting surveillance on a room in an adjacent building. One of the detectives, the skinny “Laurel”, sees Kevin's work and it turns out he's a Billy Bat fan. The other chubby "Hardy" detective picks up a page and says that the characters look familiar and accuses Kevin of translating an old "Jap" comic.
As Hardy remembers the comic he thinks Kevin is ripping off, we make another Urasawaesque time jump to 1949 Tokyo.

Note: Won the Max und Moritz Prize for "Best international Comic" in 2014.

As a child, Kasama Ryuuji watched his parents killed before his eyes by the rival, Yazuka gang. As a teenager, he finds the woman who raised him after the death of his parents, raped and murdered by the same gang. With the lost of his loved ones, Ryuuji wants nothing more to do with the Yazuka. When everything seem lost, the kind and caring, Araki, who claims to be the brother of his adoptive mother appears. Ryuuji develops a special bond with Araki but how will Ryuuji react when he learns that Araki, in fact, is the only surviving member of the Kasama gang, who has devoted his life to protecting Ryuuji. Will Araki-san, the dragon, be able to keep Ryuuji safe, or will his enemies use the young man as a pawn against him? (from MegKF by Rogue11)

NOTE: Each Hana to Ryuu Soushuuhen volume compiles 4 doujinshi volumes.

Hana to Ryuu Soushuuhen 1 (1998)
#1 Chiri Isogu Hana
#2 Hei no Naka
#3 Ryuu no Tsume
#4 Futatsu no Saikai

Hana to Ryuu Soushuuhen 2 (2000)
#5 Shinjitsu wa Yami no Naka
#6 Yomigaeru Akumu
#7 Mienai Tobira
#8 Ryuu wo Karu Mono

Hana to Ryuu Soushuuhen 3 (2003)
#9 Hebi no Rasen
#10 Kienu Juujika
#11 Karamiau Kizuna
#12 Tsuki ga Michiru Toki

Hana to Ryuu Soushuuhen 4 (2006)
#13 Kaiko to Zouo
#14 Kioku no Kakusei
#15 Aizou no Yukue
#16 Hebi no Doukoku

Hana to Ryuu Soushuuhen 5 (2007)
#17 Ai to Yami no Hazama de
#18 Yume no Mahoroba
#19 Matoitsuku Bourei
#20 Tamashii no Doukoku

#21 Tomurai no Hana (2009)
#22 Kibou no Akari (2009)
#23 Tabidachi (2010)

From the Outerworld Scans website:

Tetsushi (a 5th grader delinquent who rules over the students of Jouin elementary), Ryuuchin (Tetsushi's right hand man) and Tsuda (their sometimes-ally), are known to everyone in town as the "three evil prankster kings."

In a creepy pharmacy located out-of-town, the boys meet an old man who bestows a strange and other-worldly power upon them. Soon after, our 3 young pranksters find themselves battling a variety of ghosts and demons...!?