From Transcendence:
As the war-torn kingdoms vie for power in Ancient China, a deadly yet beautiful struggle also emerges in the seraglio of the King Xun, the King of Ding! In order to gain the terrifying King Xun's favor, Ninghu's family is determined to make her the future Queen, but King Xun is not interested in his concubines at all.

Not willing to become just another neglected concubine, Ninghu disguises herself as an eunuch servant to her brother Yuanren, the second most powerful eunuch and adviser in the kingdom. However, the moment that she enters the Scarlet Palace, Lingyu, the most influential and favored eunuch, suspects that she is a girl and begins to investigate her.

With the mysterious death of Lingyu's original servant, Ninghu decides to become Lingyu's personal servant in hope to approach King Xun. However, King Xun is absent from the palace, and as time goes on, Lingyu and Ninghu become more and more attracted to each other. Could they have fallen in love with each other?!

From Hanashi:

The start of high school life. To the girls, that also meant the start of their love lives. For brand new first year student, Takahashi Nanami (Nana for short), it was no different... She happens to end up in the same class as the incredibly popular Yano Motoharu, who rumors say that two thirds of all the girls are guaranteed to fall in love with. But will that hold true for Nana, who says that if she had to choose between like or dislike, she'd say she dislikes him!?

Note: Won the Shogakukan Manga Award for shoujo in 2005.

Senou Natsuru is a normal high school boy. One day he wakes up to find himself turned into a girl. A stuffed tiger "Harakiri Tora" comes to life and tells him to fight as a female psychic fighter "Kämpfer". Having no idea about what's going on, Natsuru is involved in the battles against other "Kämpfer".

Kämpfer is German for fighter.

In the Kokoro series:

Vol.1 - Otokogokoro (A Man's Heart)

1 & 2. Otokogokoro & Otonagokoro
Salary man Saki almost makes it home but passes out from fever just as college student Shinomiya passes by. When Saki comes to he realizes he's in a strange apartment and Shinomiya has been taking care of him for the past two days! Not wanting to be indebted, Saki tries to repay him as thanks but Shinomiya's having nothing of it. Luckily, Saki's pretty creative when coming up with a way to express his gratitude that has them both wanting more...

3-4. Kiss Kiss Kiss

5. Nibukoi (Dull Love)

6. Hiiragi-senpai no Koi no Ohanashi

7. W Pure

Vol.2 - Koibitogokoro (Heart of Lover)

Vol.3 - Koigokoro (Heart of Love)

Vol.4 - Tokimekigokoro (Heart of Excitement)

The number of chapters comprising the main story in each book is as follows:
Otokogokoro (2 chapters),
Koibitogokoro (6 chapters + omake) entire book,
Koigokoro (2 chapters + omake), and
Tokimekigokoro (5 chapters + extras) entire book.

Xolia applies for the title of "assistant to the Devil." In exchange for signing her life away, all she asks for is information. Now she's wondering if this was a good idea in the first place?

An Onmyodo School Fantasy of a Failing Private Onmyo Academy Student!!
Tsuchimikado Harutora was born into a prestigious Onmyoji family, but he can't see "spirit energy". Therefore, he's been enjoying a peaceful daily life with his friends at an Onmyo branch school. One day, his childhood friend Tsuchimikado Natsume, heir to the head family, suddenly appears. Will this cause his destiny spring into motion!?

From Hoshikuzuu Scans

Story 1) Sofure Buka! (4 chapters)
"Please no more...Save me, Nakamuraaah...!"

With the stress from work and his girlfriend, Seta's body, mind and spirit are all reaching their breaking point. Then along comes his subordinate--body pillow fanatic--Nakamura, who proposes that they become sleep buddies (friends who sleep next to each other). With his mental state stretched to its limits, he decides to try it; but seriously, with a guy?! Buuut...why does it feel so nice to be enveloped in the strong arms of his brash subordinate?

Story 2) Bed wa Futatsu Irimasen. - Sequel to story 1

Story 3) First Bite (From Nakeru BL Anthology)

Story 4) Katappashi kara Zenbu Ai
Katappashi Kara Zenbu Koi side story.

Story 5) Yokuasa no Dekigoto - Sequel to story 4

From Yen Press:

Shouta Yamakawa is in love with manga…and the 2-D girls in it! So when a casually uttered wish to have the lovely, frail Sora Nagihara-his favorite comic heroine-by his side comes true, Shouta can’t believe his eyes! But he quickly learns that while this Sora is just as cute as the one in his comic books, “frail” is the last word that comes to mind for her personality! She’s one bold, brutal babe, and she’s ready to bring the world to its knees for him, her new master?!

Failed on his job-hunting, shut-in Sagara Kurohiko went to the mountain on the day of a typhoon where he is struck by lightning and dies. But he is still alive, in a strange land with a great holy tree. To his surprise, his physique has rejuvenated to when he was teen. Brought to the academy near the tree, he is soon suspected as a spy from another country, and was brought to the headmaster. An accident happened on the way, which enraged the headmaster. Before Kurohiko can get blasted by magic, his eyes laid upon an old parchment. He took it and read the contents. Suddenly four holes appeared and black chains came out from each of it, binding the headmaster. It is then revealed that Kurohiko just recited an incantation of "Forbidden Art," an art which is extremely powerful from a legend. Apparently, no one has been able to decipher the contents of the scroll, which makes Kurohiko the only current Forbidden Spellcaster. Sparked by this, the headmaster offers Kurohiko to attend the academy.

This manga is based on the horror-style exploration/ero-game of the same name. Reiichi heads off for a part-time job interview, hoping to get money for a new bike, and his self-styled servant Kuro-senpai tags along. The "interview" is in a western-style mansion, but no one seems to be around. The two of them end up locked in the mansion and must find their way out.

Asahi Rintarou is a 2nd year high school boy who called out his senpai Shiori to a park in order to confess his love. As he readies to convey his feelings he realizes that they are not alone in the park and that someone was right behind them the whole time.

A collection of seven oneshots covering a wide range of themes.

1. A Lad’s Christmas: A jaded Santa has to get through a particularly rough Christmas.
3. TUDM: Two soldiers are struggling their way out through the thick jungle under heavy fire from the enemy.

From MangaHelpers:
One day, Serizawa fell asleep at work and had a dream about a past love that he wronged when he was in middle school. On the way home, he was involved in an accident, and a woman who knew him called for an ambulance. Now the woman has his phone number, but he doesn't know her identity. Serizawa thinks back over the women he has loved in the past, trying to determine who this woman that has re-entered his life is.

Kang Chan and Seyeon have been close friends since they were young after being introduced by their parents. After entering high school, Seyeon suddenly received a confession from Kang Chan and became aware of Kang Chan since then. Meanwhile, Naeun is displeased with their relationship. The trivial and noisy story of their love triangle and those around them...

A story about a new enthusiastic teacher, Naoki Sakura, who took up his new job in all-girls high school! He became the homeroom teacher of the first years, but the girls in the class contains full of different personalities. He declared to these girls "I want all of you to love one another!" Will he and his students be able to build a teacher-student relationship with that goal!?

With the space program attempting to travel to Mars, 21st century scientists were tasked with warming up the planet so that humans could survive on its surface. They came up with an efficient and cost effective plan of sending cockroaches and mold to the surface so that the mold would absorb the sunlight and the insect corpses would serve as a food source for the mold.
It is now the year 2577 and the first manned ship to Mars has landed on the planet and the six crew members are ready for their mission. But what they find are giant mutated humanoid cockroaches with incredible physical strength. The crew members are easily wiped out, but not before sending a transmission back to Earth. Now, humanity will send elite warriors to exterminate the mutated bugs and claim back Mars.

Note: Was nominated for the 6th Manga Taishou in 2013.

Kentarou is a plain, nondescript college student who has never had a girlfriend or any friends. After getting hit on the head by a wayward ball, he begins to notice that there are increasingly long periods of time in which he cannot remember what he was doing.

One afternoon, he regains consciousness in an apartment he'd never been to before - and sitting next to him is a young man who then tells him "You're being possessed by the spirit of my dead girlfriend"...

Summary by amoxi:
A new big beautiful guy is transferred in Hoshino's class. Wait! He's Ichinose, the troublemaker of middle school. At that time Hoshino has written a love novel between Ichinose and his new stepbrother. When the novel was discovered by a classmate, they make fun of them and triggered Ichinose's wrath. Then ichinose transferred. Maybe was Hoshino's fault? And now he's back!

A collection of stories:

• Hot Gaze in the Cold Weather

• C.5 - The Love Relationship between Mai-chan and Ecchan

• Madder Memory