From MangaHelpers:

On his seventeenth birthday, Amamiya Kota was going to ask his classmate Misora Hiyori out. Tragically, he dies in a car accident but is given a second chance back in the living world on borrowed time. He gets entered into a competition called the 13 Game where other people like Kota who were supposed to die return back to the world and given an option: locate and kill 13 other players or suffer the fate of death. Each player is assigned to a handler, mysterious beings with special powers, who use them as if they were characters in a video game. Kota’s handler, Merume, explains that there are players like him all over the country, each with a unique ability that helps them kill, and Kota has to kill 13 players within 1 year. With his demon hands ability that was inspired from his hobby of magic tricks, Kota must unwillingly participate in this cruel game if he wants to live. [vyc]

Satsuki Kakeru lost his sister by suicide and has been living a dull life ever since then. One day, he is transported into a bizarre world "Red Night" along with his friend Minase Yuka and six other classmates. In order to survive and escape from Red Night, they must defeat six black knights in order to return home.

From Heroines of Fantasia:
16-year-old Tsukimi Hina decides to get a part time job as a maid, and successfully passes her interview. One thing though: she can't use modern technology inside the house whatsoever?! Which means no vacuums, no cellphones, no laptops, etc. What is up with her twisted, but handsome, employer Asakura Shiyuusei-san? And what exactly is he hiding in his storage room...?

From Intercross:
16-year-old Hina's first job is with a 19th-century British enthusiast, Shuusei-san, as his maid. Even the way of cleaning has to be from the 19th century! Even so, this sweet gentleman makes Hina's heart beat so fast! There is actually another person in this residence, Mary Lou. She's as cute as a doll, but... she's, she's... a ghost?!

In this small town, within the 49 days after a person dies, you can see the dead's spirit. She once admired this small town where you can still spent time with the ones precious to you within these 49 days, but...

Includes two oneshots (not yet scanlated):
Soko ni Koi Ari (そこに恋あり)
Kimi wa Nanimo Hoshigarazu (君は何もほしがらず)

From ShoujoMagic:
1. 38°C
Taiji's normal body temperature is 38 degrees Celsius, or so he says, but Shiina thinks he's full of it. Taiji is a friend with whom Shiina can always--and does always--fight... Until Taiji unexpectedly confesses his love! Shiina begins to run a fever, but is that the only reason she's getting so hot...?

2. Solution Maze

3. Heaven in Jail

4. Winter's Aquarius

Collection of short stories:

• 37℃ Kissu
Naoki was a very cool and good looking guy, but somehow after meeting Fumika-chan, he's not cool at all, but very cute?!

• Himitsu no Namida (Secret Tears)
He saved his second button for her, but on their last day, she handed him a love letter to give to his best friend. Instead of delivering that letter, he kept it himself, and asked her to go out with him instead...?

• Caramel Kiss
Atsushi-sensei is Kawahara's first love, will he be able to accept her affections?

• Shounen Knife
Until Riki moved in, the house next door to Mimi's was always vacant. Riki saved Mimi's cat, but it seems that he isn't as well mannered as she first thought?

• Extra from Kiss, Zekkou, Kiss Bokura no Baai.

1-3) 37°C no Boyfriend
Wakaba got locked up in an elevator with a completely strange guy. Moreover, they happened to share a kiss. He's someone she'd never meet again... or so Wakaba thought, but it turned out that that guy, Chitose, is the boyfriend of Nao, her friend!
Nao introduced a surprised Wakaba to her upperclassman in her club, Takaomi, but no matter what, Wakaba can't forget about Chitose...
- Awakened Memories

4) Tsukiakari no Himitsu

5) Haru ni Naru Made Matte
(Also included in Houkago, Kimi to Koi o Shite.)

About a play-girl goddess from heaven who is stripped of all her 'goddess' powers and reborn as a human. The story progresses as her incarnated character learns to live, love and find what true happiness is all about.

From Noctis Op.92:
What exactly is the difference between a robot and a human?

In a dystopian future in which robots are becoming increasingly commonplace, a young boy named Hogu lives in near poverty with his grandmother and sister. Though he innately possesses a kind soul, he is ostracized by his classmates and frequently bullied. At the beginning of the story, we find Hogu, friendless and alone - until he meets a robot girl...and our story begins.

Thief Gintonic seeks the mysterious treasures known as "The Three Hearts". One night a mysterious woman falls from the sky claiming to be an escaped Princess from a sacked castle. As fate would have it, she has one of The Hearts. But is she really who she says she is? And will Gintonic let her live to fulfill her mission?

There’s one thing I understand when I became an adult.There’s nothing special about boyfriends, sex and kisses. but if I think that, will I be able to find love?

1-2) Can't Kiss for 24 Hours
A math teacher who has an intense relationship with the problem student, Kikusui Kiyoya. Even though they were a couple in love, one day, Sensei suddenly wants to break up...?

3) If I Didn't Have You
Fujisawa Yuu just moved to a new town. On the first day of school he's warned to stay away from Nanatsuki Haruki. The word around school is that Nanatsuki who is actually 20 years old will sleep with anyone, but only at school. The mystery is why he only sleeps with people at school and why hasn't he graduated yet?

From Tokyopop:

Akira - who later appears in the CLAMP School Detectives manga series - is a dapper, debonair young thief-for-hire who becomes the object of 5-year-old Utako's affections.

From Boys On Boys Love:

1-2. 2-dome no Koi no Hajimari wa
After being harshly dumped by his lover, Kousaka Yuuki, a shop manager at a restaurant, swore that he would never love again. One day, he meets his ex again when he unexpectedly shows up at Kousaka's shop. It was then completely exposed to Matsuoka, a kouhai at work, that he dated a guy. Kousaka was shaken that his past was known to Matsuoka, and worried that he would look down upon him, but Matsuoka forcibly kisses him and says "I love you" to Kousaka...!?

3. Gekiai Honey
Sasaki Ryoutarou, a part-timer at a restaurant leading an ordinary life, suddenly met his old classmate, Mio. Mio was once a gloomy guy ignored by all, but is now a cheerful, completely changed guy. He claims to have been searching for Ryoutarou to be his lover because he couldn't forget about him, even after being rejected a long time ago. Mio changed his style because he had heard that Ryoutarou's type is a cheerful person. Ryoutarou refuses to go out with him, to which Mio responds: "go out with me for a month, if you don't fall in love with me then I'll go back"...

4-5. Honey Trap
You is in love with his best friend Shinji. Afraid of ruining his friendship with Shinji, he doesn't confess, and breaks off all contact with him. Three years later, running away from some stalker, he enters a building and asks for help. However, it turns out that the man living there is his ex-friend Shiniji, who is now a detective...

But what will happen when Shinji suddenly asks You to be his lover?

6. Bokura no Koi no Hajimari wa

- Extras
Is a small continuation about the first story.

N/A

From Chibi Manga:

5 years ago, Shin was Yumika's private tutor. Now this Shin-kun comes to Yumika's high school as a teacher trainee! But their love from 5 years ago will most probably start to bloom again?!

From Midnight Scans:

Yumika’s first love was her tutor Shin. As she hope to meet Shin once again, which really happens, how will Yumika proceed on to confess to Shin about her feelings…

From Beautiful Soup:

"1999" is an angsty and widely varied series about a bunch of teenagers. One of them is the son of a drug lord and so as you can imagine, all sorts of shit goes down, surrounded by a backdrop of convoluted and fluctuating interpersonal relationships.

This is a plot heavy manga with some mildly-explicit sexual activity.

MAL:
This plot takes a new twist to Romeo and Juliet's forbidden love. It's July 7th, 1999 in Shanghai and there are two gangs fighting for control. Only in the ceasefire zone do people live in peace. In a chance meeting Xiaoxue, who is part of the Toulon's gang, and Dawu, from the Xianglongji's gang meet by chance and without knowing they are enemies. In the heat of the moment Dawu takes him to a place he has the keys to in hopes Xiaoxue will join him, but is turned down. With a simple kiss he leaves Dawu not knowing they will meet again, but in very different circumstances

After she died from an accident, Ria become angel No. 5623. She could not forget her life from when she lived. She misses Ban Ji Hwan, her boyfriend on Earth, day and night.
1 year later, Ria happened to see Ji Hwan's name on the death list, the list of every names who is about to die in 100 days. Ria begged high-ranked angels to let her save Ji Hwan. Ria entered the body of So Hae, a shy girl who is tired of her life, the opposite of Ria's personality. Enduring the bullies from step-siblings of So Hae, Ria did her best to bear everything in order to look for Ji Hwan. But when she found him, Ji Hwan cannot recognize Ria...

An art college students moves in Venice to study, she starts to live in her new room, part of an old huge historical mansion and she discovers a new world of secrets linked to her young, mysterious landlord. A gothic romance story and a vampire tale which flows around Venetian laguna and roman museums; a manga rich of suggestions and images with a passional storytelling, a deep noir drawing style and melancholic mood. From Italians to Japanese. This was created for Kodansha, published on Amie. You read it Japanese style.

Kazao is happy with his life on Mirai ("Future") Island. Sure, his parents abandoned him after he was born, leaving him to be raised at the orphanage-like facility, but his life is comfortable and has his friends, especially the lovely Eiko, the girl he loves. One night, however, he has a horrible nightmare where he sees himself die in a motorcycle accident. After that, everything changes. The next day, his parents are miraculously "found" and he is torn from his idyllic life and Eiko's side to be thrust into a world he knows only from television shows and school assignments. Dropped unceremoniously in the middle of a city with only a sketchy map for guidance, Kazao is saved from wandering aimlessly in search of his new home by the cute and forward Yuu, who turns out to be in his class at his new school as well. Despite his best efforts to accept his parents' sudden return and Yuu's friendly overtures, Kazao can't shake the feeling that things aren't quite right. Nor can he forget Eiko. Why did his parents wait sixteen years to call him back? And why is the piano the only used piece of furniture in his parents' new house? The mysteries begin to pile one atop the other as the lies fall apart in this intriguing story of future possibilities and innocent romance.