A student disappears suddenly and in his place a mysterious note is found. This is the beginning of the unbelievable things to come in the future.

From Chibi Manga:
I thought I didn't need something like or love. I'm small, and I have a height complex. I am Koeda Tsugumi (First year High). One day, Sena Masamune from the next class, saw my body by coincident...!? But, after finding out, I was always with him and he hid my secret that I'm actually a girl, and slowly my feelings grow....A useless girl in love, a pure slow love!

Alternate:
Short skinny girl living her life with no thoughts of love, until one day popular hot guy sees her exposed rib cage on accident. Self conscious she leaves the room dropping a hairpin the process. Hot guy picks it up, and returns it to her. This signals the start of something more?

Serina arrives at school one day to discover her desk has been vandalized—someone's scratched the lyrics to a love song on it...and that someone turns out to be Mizukawa-senpai, a boy who's one year her senior. She wants to get to know him better, but if his frosty demeanor is any indication, she doesn't have a chance! But it seems he might be awkward—not simply mean—and before she knows it, she's asking him out...! With each passing day, her heart races a little faster!

Ran is always called the Takane no Hana because she stands out. And her classmate, Akira, approaches her normally...!? Takane girl x flower shop boy's first love story is beginning!

An after school club originally founded on the obsession of Fish Cakes, containing girl members with odd kinky traits and a male member who has trouble maintaining a relationship longer than a month.

From Lovesick Alley and Sunday Scans:

Tsubomi is in her second year of high school and has a crush on her homeroom teacher. She plans to give her teacher a birthday gift, but unfortunately his birthday falls on a weekend... After finding out that her classmate Fuma Yabuki is her teacher's cousin, she tried to get him to help her but despite being related to her homeroom teacher, who is nice and warm, Fuma is very standoffish and doesn't want to help her out. Will this be the start or the end of Tsubomi's love?

The protagonist lives and works in a boarding house and has a phobia of boys, however she finds herself having to manage her fear when two new boys are hired in the boarding house who will live and work there. One is a silent boy who confesses he hates girls, the other is a school friend who can't stand the protagonist because of her elusive character...

Mikoto Yuuichi (called witch due to a similar sounding surname) is the student council president and is constantly courted by a girl named Naitou.

A 4-koma comedy about the daily antics of the fairly normal Imura Sousuke, and the "delinquent" Sakino Mizuki.

From CoyoMoose & Turtle Paradise:

Third-year high school student Tachibana Kyou's world is shaken when a green-horn nurse suddenly arrives at his exclusively male school - the doe-eyed, baby-faced, and irresistably adorable Hirota Natsu. Completely taken with the new faculty member, Kyou abandons his playboy lifestyle for her, having found true love for the first time... But what will fate have in store for these two, engaged in the taboo relationship between teacher and pupil...!?

Two students, Li Shang Xian and Qiao Xin Yi, live their lives as normal senior middle school students, while secretly hiding their true identities: Mages of Law. But on one eventful day, Qiao Xin Yi reveals her true identity of being a Law Mage in an attempt to rescue Li Shang Xian from a deadly attack of a Corruptor, but to her surprise, Li Shang Xian has a secret to show of his own! Join Li Shang Xian and Qiao Xin Yi, as they make numerous sacrifices and attempts in order to fight and exterminate the Corruptors that are plaguing the world in which they live in.

Once upon a time there was a wonderful prince… A super rich and handsome prince with a genius IQ of 500, extraordinary physical prowess… An outrageously overpowered super star…!! What will happen when this ridiculously overpowered ultra-high spec boy and a certain ultra-level-headed ordinary girl meet…?!

Akihime is a seemingly normal girl attending junior high school, but she is actually the daughter of Ryokuhouzan's tengu. She lives with her mother in the human world, living a normal human life. However, her childhood friend Shun is constantly trying to convince her to go to the mountains with him, so that they can become tengus together. Despite his continuous urgings, Akihime refuses because she has feelings for her classmate, Takeru-kun.

Machi de Uwasa no Tengu no Ko won the 2009 Shogakukan Manga Award for best shoujo.

Mimibukuro-san is self conscious of herself, and can't really talk to anyone. It's up to Makoto-kun to help her out and make friends with each other. However, that's not the end of it. There is someone trying to disrupt the two. Will they succeed, or will they join in...

During the high school entrance ceremony, Koga Eito from the special class helps Kasuga Niina from her poor health. His gentle manner captivates Niina, making her confess her feeling towards him. Thus, the trials in love of this couple begin.
As time passes, Niina finds it difficult to continue loving him since there are instances when he seems to be playing with her feelings. For her, going out with Koga may bring a grim future to her.

Asahina Wakaba is a shy and slightly awkward girl. She is coerced by her classmates as a punishment game to confess to Iruma Haruto, the number one most hated boy in school. Though her relationship with Haruto starts out with an air of gloom for Wakaba, her depressing school life is dyed with color when she discovers that they share more in common than what she thinks.

From Yuri Project:

Kinosaki Emu, captain of the table tennis club, is a large-breasted high schooler who loves table tennis even if she's bad at it.

Opposite her is Yajima Esumi, her one-and-only club member, a sadist who's amazing at table tennis. Esumi throws insult after insult at Emu like calling her a fat pig or only good for her boobs.

Not sitting idly by, Captain wishes to restore her dignity. She gives her all in matches and tries to get new members to join the club. But will this be enough? Will Captain restore her dignity?

Rosalia, a Marquis’ daughter, for some reason only lived within the premises of the Marquis’ residence. One day when she was sixteen, she fell in love with a red headed knight who wandered into the garden by accident. It was at that moment the powerful Marquis’ daughter felt something trigger― A knight who is a reincarnator, but doesn’t realize that he’s a capture target in an otome game and the main villainess, who began to change once she met the knight.

The heroine who has been reborn with the knowledge of the game would be the fall of Rosalia, however, it does not go through according to the scenario…

“What are you?! You’re the villainess, aren’t you?”

“Villain? You think you could play such an outrageous role? I am a genuine villainess.”

Kugami Sugara just wants to lead a peaceful school life.
But being chosen by the beautiful and talented Shirasagi Yui to be her pseudo 'sister', her life is anything but peaceful.
And to make things even more interesting, Yui's cold but capable identical twin sister (and also student council president), Shirasagi Ui, also takes an interest in Sugara.

From there, things go as well as you might expect in this yuri comedy!

Author's Twitter: https://twitter.com/ndoromaru

From StarryHeaven:

I’m Anna. I’m 14 years old and I’ve just entered the ninth grade. Sou and Hinata, who live in the same apartment complex as me, are my childhood friends and we’re all the same age. I thought that from now on we’d become even closer friends, but then Sou suddenly did that to me…!!