From Fantagraphics:
A DECADE-SPANNING JOURNEY INTO DARKNESS
Even as butterflies ominously proliferate in town, the rumor of a mysterious creature lurking in the tunnel behind the school spreads among the children. When the body of Arié Kimura's mother is found by this tunnel's entrance, next to apparently human traces, the legend seems to be confirmed. Is the end of the world coming? In order to appease the wrath of the beast, the children decide to offer it a sacrifice: The unfortunate Arié, whom they believe to be the cause of the curse, is shoved into a well that leads to the Nijigahara tunnel — an act that in turns pushes Komatsuzaki, the budding thug who has carried a torch for Arié for a while already, entirely over the edge.
But this is only the beginning of the complex, challenging, obliquely told Nijigahara Holograph, which takes place in two separate timelines and involves the suicidal Suzuki; Higure, his stalkerish would-be girlfriend; and their teacher Miss Sakaki, whose heavily bandaged face remains a mystery; and many more — brothers, sisters, parents, co-workers, teachers, aggressors and victims who are all inextricably linked to one another and all will eventually — ten years later — have to live with what they've done or suffered through.

From Hidoi~! Translators:
Miu is an average high school girl who lives in a fantasy world dreaming about the day she'll find her destined one, just like in the manga stories she reads. What she doesn't know is that her prince might be closer than she thinks.
One day after getting punished by running around the school, she gets hit by a motorcycle at the school gate! When she sees it's a guy she thinks it's her so awaited prince. But later she'll find out a secret about this guy and his twin brother...

From Lililicious:

Cat's Eye Hall is a mysterious shop that exists to guide lost hearts. If your heart is lost, follow a black cat and you might just end up here...

In the Nekomedou Kokoro Tan series:

V.1 - Yuri Shinjuu (A Yuri Double Suicide)
- A Yuri Double Suicide
Shiho and Hiyori think they can only be together in death. But as they're looking for a place to commit suicide, Hiyori disappears and Shiho follows a cat to a mysterious shop called the Cat's Eye Hall.
- Beautiful, Cruel Pride
- Hana ga Chittemo
- Shitataka de Ite Bukiyou na
- Kaminagahime

V.2 - Shoujo Hakumei
- Shibaru Ito
- Stella Maris
- Satou Kashi wa Yume wo Miru
- Amai Moumoku

V.3 - Renai Higan

Collection of short stories.

>Nui ja dame!
Yui finally got a boyfriend and his name is Sota. Everyone sees him as a quiet cute guy while he's really a wolf in sheep clothing. It was almost Christmas eve and Yui want them to go together. Earlier she rejected him while he was trying to get them to have sex. The excuse was 'If I have sex I won't be able to see UNICORNS again!'. He seems 'fine' with it and went along. When her friend offered condoms to Sota he rejected it because it wasn't that kind of relationship...

From Taruby:

Shiraishi Yayoi was a relatively unremarkable school girl, although a little clumsy, before a experimental accident changed her life forever. She was forced against her will by her father, self-proclaimed genius physicist, Shiraishi Sensei into a teleporter with a cat , and like in the movie "The Fly", she combined with the cat.

Now, whenever she gets excited about anything, a pair of cat ears and a tail pop into existence. In the "catgirl" form, she has super powers, but the major drawback is that she also behaves like a cat when presented with the proper stimuli, like the sight of mice. She also has a boyfriend, but her "problem" tends to interfere in their dates since her excitement inevitably leads to her transformation into a catgirl.

Love Story about two childhood friends who met each other again after seven years apart.

Hyoudou Kaname and Shishido Makoto are two abnormally tall (over 180 cm!), sharp-eyed high school girls. That, in addition to Kaname's emotional instability and violent outbursts, has instilled a fear of the two girls in all their classmates. But, though they're bad at dealing with people, they are actually normal girls. They just want to hang out with friends, have boyfriends, and enjoy high school like other girls, but they fail whenever they try. If they don't get discouraged and continue to work at getting to know others, will a day come when they can smile and be happy? It's a high tension school comedy drawn with a unique style and tempo.

Eri Yukizaki, is a girl locked in battle with a chain-saw wielding incantation of true evil. But like the demons that boil inside her heart, the 'Chainsaw Man' doesn't seem to die no matter how much she stabs him. As she fights, a young man, Yamamoto watches, love-struck, wishing he could be more than just her useless bicycle courier.
An action-packed romance, digging into the human psyche, exploring the demons that buries us in sadness and misery.

Omoigabuchi, a pond with a legend attached: "If two people go in together, they will be bound to each other for life."

The story of three couples who get dragged into this love pond.

1) Odeko no Mahou
One day during soccer practice, Eiko gets hit on the forehead by a ball kicked by Shigeru. The next day, a strange word appears at the very spot, and it changes to reflect her emotions. What happened to her forehead, and what is it supposed to mean?

2) Keishi no Uta
This chapter consists of 3 unrelated acts.
~Act 1: Aida Misaki likes the guy sitting in front of her. She stares at his back daily, hoping that if he'll turn around, she'll confess.
~Act 2: Yamato Dia is a member of the drama club. Although he's a member, he barely gets any lines, and feels like he makes no difference to the club.
~Act 3: Tamako Ryoko is the leader of the swimming club. Everyday Yasui Chiryoshi and his friends peep at the swimming club. Although these two argue everyday, once Tamako leaves the club, she feels like something is missing to her quiet life now...

3) Moshi Moshi.
Tateoka Mori is your typical 17 year old high school brat. She often clashes with her sensei, the 25 year old Matsubara Masakazu. When she was swapping with her her nee chan, disguised, to attend a blind date party in her stead, she encounters none other than that sensei. As he failed to recognise her disguise, she hatched up an ingenious plan to prank him- by becoming his girlfriend!

4)
Kumiko have for a long time had a one sided crush on her neighbor, Yoshirou, but he always rejects her when she asks him out. One day he promises that if it's not raining the next day, he'll go on a date with her! A pity that the weather forecast says it'll rain that day ... can a wish to a teruterubozu change that?

A guy likes a girl in his class so he confesses to her, only to find out that she has vines growing on her body. What is this mysterious affliction, and how does it affect their love for each other?

A story about two classmates, Sahoko and Rio. Rio is depressed and self-abusive due to lack of loving relationships with her "family" -- which consists of her negligent father, overbearing, selfish stepmother and stepbrother; and Sahoko soon becomes her only comfort in life. Sahoko on her part has a frigid relationship with her overprotective parents, and lives with her aunt by consequence.

A girl who can see spirits opened up a manga and read "Those who read to this point in my manga will die without fail on the same day". Terrified, she tries to break her curse, with a jumpy spirit who wants to marry her...?

On campus, student council secretary Oniyuri Itsuki and student council president Himeyuri Shizuku are popular total opposites. While their respective fans are divided into factions, their actual relationship is....!!

From Divine Sanctuary:

Lilith is a phantom thief who is after genius artist, Michelle Corradi’s portrait. After she had already stolen some pictures, Michelle had the idea to catch her. When she announces to steal his new artwork he met her and fell in love with her. What will he do to meet her again..?

A guy likes a girl in his class so he confesses to her, only to find out that she has vines growing on her body. What is this mysterious affliction, and how does it affect their love for each other?

Kouta's school-year is off to a great start; this year he and lovely Ayano are in the same class—and they're sitting next to each other! Here's the problem: whenever Kouta gets excited he passes out—and wakes up in a stuffed toy. (No, he's not cosplaying—he is the stuffed toy.) It's never the same toy and it always seems to have some sexy girl hugging it close. Then his childhood friend Ako gets involved and Kouta begins to realize Ako is not a child anymore...

From Wildflower Scans:

When her father is laid off and the family is facing tough times, middle-schooler Kousaka Yayoi selflessly offers to give up her dreams of being a high school student to contribute to the household. Fast forward to a few years later, where Yayoi is about to be given a full-time position at her office job—the only problem is that it requires a high school education! What awaits the 21-year-old high schooler at Hoshinomiya Academy?