From Forbidden Garden:
After a bitter past love experience, Mr. Cool lives a boring and ordinary life. Everything changes after he meets a girl named Ann. Not long after they start dating, he learns that Ann is Angel's younger sister, his former girlfriend who had gone missing. Things don't go so well when Elvin confesses to her. The hidden past between them slowly becomes clear and...

From Tokyopop: A lonely yet caring 15-year-old Chiaki, the half-angel daughter of the Archangel Michael and a human woman, welcomes into her home a dejected devil Ororon who pledges to stay at her side forever. Both of them have been ostracized from their respective celestial realms--Chiaki because her origins are impure and Ororon because he is the youngest son of the Lord Devil and therefore a threat to his older brothers for leadership of the underworld. As various agents of heaven come by to destroy the angel Chiaki, she learns that having the incredibly powerful Ororon by her side is useful. And as assassin after assassin comes to eliminate Ororon, he learns that Chiaki can teach him a valuable lesson about the sanctity of life.

From Viz:
Delve into the tortured past of Earl Cain C. Hargreaves, charismatic heir to a wealthy family full of secrets, lies and unthinkable crimes. Follow the young Cain as he attempts to unravel the secrets of his birth, all the while solving each new mystery that comes his way.

----

In the Hakushaku Cain Series:

1) Wasurerareta Juliet

Includes 2 oneshots:
i) The Boys Who Stopped Time -
England, year 1918. Rupert enrolls to his new school just a few days after the murder of a maid called Noelle. He's the type that just can't sit still, so when he meets Noelle's sister, he's determined to help her find out who murdered her sister...

ii) Double -
When they were children, Ren helped his friend Emilio start his career as an actor. But when Ren didn't have any news from Emilio for two years, he decided to go to New York to look for his friend...

2) Shounen no Fukasuru Oto

3) Kafka

Includes 1 oneshot: Ellie in Summer Clothes

4) Akai Hitsuji no Kokuin

5) God Child

From ShoujoMagic:
There is a legend in the kingdom of Paros -- a legend of the Sword. It is said that if one who is unfit to rule should wield it, it will mean the ruin of the kingdom. As sole heir to the throne of Paros, Princess Erminia must accept the Sword and a husband when she comes of age on her next birthday. But the princess refuses to wed any man who is less of a man than she -- which excludes every man in the kingdom! Just when Erminia is ordered by her father the king to wed her foster brother Yurias, she has a fateful encounter with the unfortunate, beautiful maiden Fiona..!? "The Sword of Paros" is a miraculous romantic fantasy about defying convention, transcending gender and status, and knowing oneself.

A collection of short stories. Note that the vast majority of these stories contain heterosexual romance themes. A few stories explore transgender issues, but it's a stretch to call them shounen-ai or BL romances. This series demographic is josei.

Le théâtre de A
1.Oeufs D'ange - Tenshi no Tamago
A man is asked by a young painter to be her model.

2. Velvet Going Underground
A doll becomes a super idol. Hijinks ensue.

3. Childhood's End
Alastair runs away and meets the Rabbit.

4. Bite Me Something
Allistaire followed Mr. Rabbit all the way to Wonderland. Will he be able to find him among the crowd?

5. Long Along Alonging
A girl asks a vampire to be his apprentice. But what is her motive?

6. Till Dawn
In a dark tower, a caged voice is singing until a hunted man enters the darkness.

7. Leçon un
Sequel to Long Along Alonging.

8. My Skin on My Back

9. Highland Walker
Sequel to Leçon un.

10. Perfect World
The story of a young wife whose husband is infected with a fatal disease called Flower-Blossomitis.

11. Perfect Lady
Sequel to Perfect World and drawn especially for this book.

12-13. Looks Like a Teaspoon
A boy named Allistaire is often teased at his all-boys school. One night he dresses like a girl and stumbles upon the boy who often bullies him, Simon. Allistaire runs off into a tower and as Simon runs after him, we see the sign "Welcome to Wonderland" hanging by the tower's door.

14. The Pearl Blue Story
Do you believe in mermaids? Coggy, a young boy finds a mysterious lady laying down near the shore of the beach. He brings her home to help her.

15. I Am a Piano
A piano tells the story of her life and the people she encounters.

16. Parade

Le théâtre de B
1. Noël
A short story about a holiday romance.

2. Teddy Bear Satsujin Jiken (The Teddy Bear Murder Case)
Four murders have taken place at an all girl school. Lying beside each of the victim was a teddy bear with one missing limb.

3. Yonshimai Satsujin Jiken

4. A is for Alice
Alastair, a grown man, is off to follow the Rabbit once again to return to Wonderland.

5. Nedai no Musume Atelier no Musume (The Bedroom Girl, The Sculpture Room Girl)
A story about a girl in her death bed finding another chance in life in the body of a doll.

6. B&W (Black&White)
A story about a boy waiting for his sister.

7. Le Jardin du thé (The Tea Garden)
A mysterious story about a poor young man who orders a kind of tea called Huan Ying – “The Illusion”.

8-9. Free Fitting for Her
A priest and his captured vampire must save a naive and selfish young girl from the murderous desires of a Lolicon. But perhaps this girl isn't all that she seems.

10. Rose Dusk, Pale Moon

11. Hello, My Sister

12. The Happy Prince

13. Welcome to Wonderland
Simon, Alastair's old classmate, is now a grown man who bumps into his childhood Wonderland traveller.

A collection of short stories. Note that the vast majority of these stories contain heterosexual romance themes. A few stories explore transgender issues, but it's a stretch to call them shounen-ai or BL romances. This series demographic is josei.

Le théâtre de A
1.Oeufs D'ange - Tenshi no Tamago
A man is asked by a young painter to be her model.

2. Velvet Going Underground
A doll becomes a super idol. Hijinks ensue.

3. Childhood's End
Alastair runs away and meets the Rabbit.

4. Bite Me Something
Allistaire followed Mr. Rabbit all the way to Wonderland. Will he be able to find him among the crowd?

5. Long Along Alonging
A girl asks a vampire to be his apprentice. But what is her motive?

6. Till Dawn
In a dark tower, a caged voice is singing until a hunted man enters the darkness.

7. Leçon un
Sequel to Long Along Alonging.

8. My Skin on My Back

9. Highland Walker
Sequel to Leçon un.

10. Perfect World
The story of a young wife whose husband is infected with a fatal disease called Flower-Blossomitis.

11. Perfect Lady
Sequel to Perfect World and drawn especially for this book.

12-13. Looks Like a Teaspoon
A boy named Allistaire is often teased at his all-boys school. One night he dresses like a girl and stumbles upon the boy who often bullies him, Simon. Allistaire runs off into a tower and as Simon runs after him, we see the sign "Welcome to Wonderland" hanging by the tower's door.

14. The Pearl Blue Story
Do you believe in mermaids? Coggy, a young boy finds a mysterious lady laying down near the shore of the beach. He brings her home to help her.

15. I Am a Piano
A piano tells the story of her life and the people she encounters.

16. Parade

Le théâtre de B
1. Noël
A short story about a holiday romance.

2. Teddy Bear Satsujin Jiken (The Teddy Bear Murder Case)
Four murders have taken place at an all girl school. Lying beside each of the victim was a teddy bear with one missing limb.

3. Yonshimai Satsujin Jiken

4. A is for Alice
Alastair, a grown man, is off to follow the Rabbit once again to return to Wonderland.

5. Nedai no Musume Atelier no Musume (The Bedroom Girl, The Sculpture Room Girl)
A story about a girl in her death bed finding another chance in life in the body of a doll.

6. B&W (Black&White)
A story about a boy waiting for his sister.

7. Le Jardin du thé (The Tea Garden)
A mysterious story about a poor young man who orders a kind of tea called Huan Ying – “The Illusion”.

8-9. Free Fitting for Her
A priest and his captured vampire must save a naive and selfish young girl from the murderous desires of a Lolicon. But perhaps this girl isn't all that she seems.

10. Rose Dusk, Pale Moon

11. Hello, My Sister

12. The Happy Prince

13. Welcome to Wonderland
Simon, Alastair's old classmate, is now a grown man who bumps into his childhood Wonderland traveller.

From Tokyopop:

High-school student Moon Bin Lee has difficulty sleeping due to a recurring nightmare: he's stranded over a thousand years in the past chasing a dark-haired girl into a deep abyss.

Before long, the nightmare overwhelms him, and he is unable to tell whether he is Moon Bin, a Seoul teenager at the end of the second Millennium, or Sa Kyoung Kim, the son of a prominent warrior family in the middle of the first Millennium. People in his present-day life assume roles in his historical life as he struggles to learn exactly who he is and what he's expected to do, straddling a transmigratory portal through time and space.

In the present, his school's kendo club battles to stay in the championships... but in the past, Moon Bin finds himself at the threshold of a territorial dispute on the plains of Mongolia.

From Hee Jung Park comes ten stories of love, sadness, longing and alienation. A young man finds himself continuously drawn into the orbit of future suicide victims, while another finds redemption in an unlikely ally. And an apathetic lover can only enliven his pallid relationship with the crimson color of blood...

1) Blood
2) So Long...
3) Crazy Guy
4) Feel So Good
5) Insomnia
6) Ember
7) Kwanglim is Amazing
8) Music Box
9) Ul Heul Lee
10) Crybaby Angel

Based on the visual novel Tomoyo After (a Clannad spin-off), this manga retells the story from Tomoyo's perspective.

From Tokyopop:
An introspective, character-driven series, Tokyo Babylon reads like a manga version of The X-Files. Its story -- a modern-day fantasy -- follows a young onmyouji (spiritual medium) on his quest to protect Tokyo from evil spirits.
Teenaged Subaru Sumeragi is the 13th head of the Sumeragi clan. Together with his twin sister Hokuto and the mysterious veterinarian Seishirou, Subaru travels around Tokyo, calming the ghosts that threaten the city.

A collection of oneshots:

1) Tokyo Ants
A special security group consisting of highly-skilled people rescues a hostage.

2) Enma 1 & 2
Two different stories about people who can see electricity when someone tells a lie. (Enma 2 story by: Ookawara Ton)

3) Butterfly: Swallow Tail
About a boy who can see swallowtail butterflies around people who are going to die.

Short story collection of a variety of more mature Tezuka work. The story "Clockwork Apple" was borrowed from the book, before the movie was made, but has very little to do with the book either as Tezuka admits to writing it without reading Clockwork Orange.

From Operation Boredom:

Jin, son of a Count, has a dark past that follows him everywhere. Now a pirate, he's recently acquired a new set of slaves to sell. However, one of them, Lisa, sparks something inside Jin. Could she be the one to get through his cold, ruthless, and dark heart and see what's really inside him?

The third entry from the infamous God series of web manga. This is what happens when the creator of "Umbrella Sword" tries to make a love comedy.

From iskultrip Scans:
Due to the influence of the "Dragon veins", some young men and women awoke as "those with power". They'll discover their "star of fate" in a struggle to the death with the "oni" attacking Tokyo!!! The super popular action anime has become a fantastic comic!!

From Loyal Kiss:

Guo Guo's father had wished for her to go to college, so when he died, her mother tried to fulfill his dying wish more than ever. As a result, Guo Guo constantly skips school. Lian is the only one who can help her. What will her final answer be?

A collection of shorts by Byungjun Byun, artist of young sensible works on the life in the city, including "Princess Anna" and "Run, Bonggu". Many included shorts have received renowned awards from Korea and Japan.

Hachiouji Tarou is an average 2nd year high school student. Since his father died, leaving him as the head of the family, he’s been constantly pulling his brother out of trouble. One night, when he came back home, his mother's head was rolling on the floor, and an evil spirit had hold of his younger brother. Instead of helping him, he hesitated and stood frozen with fear while the spirit got away with his brother. Now Tarou is on a quest to find his brother and exterminate evil spirits.

A story of three childhood friends - Colo, Cookie, and Naomi - who grew up in a sleepy backwater town on an uncivilized planet. They struggle to get by while holding on to their dreams of leaving town and finding a better life but can their friendship endure the tests of time? Can it withstand invading armies, broken dreams, conflicting ambitions, divided loyalties, jealousy and even betrayal?

Based on the visual novel of the same name. In 1986, between October 4th and 5th, members of the Ushiromiya family gather on the secluded island of Rokkenjima to discuss the division of the family's massive fortune upon the impending death of the family's head, Kinzo. However, when a typhoon traps the eighteen people present on the island, six people are mysteriously murdered. The remaining people struggle to survive as the murders continue, supposedly by the will of the legendary Golden Witch, Beatrice.

Other manga:
+ Triage X manga
+ Sidonia no Kishi manga