From Aerandria Scans:
Bai-Yao’s father is the owner of one of the largest media companies in Asia. She is beautiful, rich and popular so she is considered as a modern-day princess.

Even though Bai-Yao is being railroaded into an arranged marriage by her mother, our princess is in a secret relationship with the famous male singer Yin, who is represented by her father’s company. Working at her father’s company is Tien, an errand boy with dreams of becoming a songwriter, who also happens to adore Bai-Yao.

The trio’s lives are entangled when a unexpected death happens.

Note:
Billion Princess is on hiatus. The creator hasn’t been actively working on this series.

1-3) Bijin Kakumei
During sixth grade Yuki made a love confession to Shin, an extremely beautiful boy. She was extremely shocked when he started teasing her and called her fat and ugly!!
Three years later, Yuki has become beautiful by putting in great effort everyday because she wanted to get back at Shin. She transformed into a very beautiful girl!
She was accepted into the same high school as him to plot her revenge, but her childhood friend Migiwa who knows everything about Yuki's past is attending the same high school!?

4) Gothic Boyfriend (ゴシック彼氏)
Narusaki-Senpai is a famous and widely sold horror novelist, while Himeno loves to write childrens' love stories. She expresses her opinion on her Senpai's writing, but right as she says so, she knocks right into him! Narusaki takes offense to her opinion, and kidnaps her from her sanctuary of cute to his dungeon of horror!

5) Tough Girl's First Love (暴れん坊少女 First Love)
Izumi is considered the "Deity of Girls" (or protector) in her school, but there are sometimes limitations to what one person can do by herself. Kaidou-Senpai steps in, causing her to develop a crush over him.

Princess Aurora,Laira was awoke from coma and realized that herself is not a living thing but a doll.Her fiance,Prince Erique has been killed by a mysterious guy.Laira decided to joined FLAM, a military organization at Pillatus that hunting vampires to revenge her fiance's death.She meets Veltrich, prince at Pillatus who had a similar face with Erique. Nevertheless,in fact that similarity had a prove that he is not Erique. Laira starts to worry if she fall in love with Veltrich and betray her love for Erique.Where is the way of love Laira now?

There was a legend about a blind goddess who fell in love and was left heartbroken... "Why did you leave me? I vow this life and every life after I don't want to ever hear your voice again! I will forever take you as my enemy..."

From Ambrosia Scans: With the completion of the human genome in 2014, Japan has gone all Gattaca (good movie, i.e. genetic engineering) and, in 2031, a boy gifted (or scientifically crafted) with a special touch repetitiously sees a strange dream before him.

From Which Scanlations: Ever since Fune Momohara was told that she was just like a "guy friend" by the boy she liked, she's been bent on becoming the ideal girl. But when she meets the perfect guy who turns out to be more than a little pretentious, she realizes that it can be difficult to keep up appearances!

From Nekohana:
Rich young Master comes across a girl alone and abandoned during Christmas. He decides to take her in and name her "Mike". Now he's in high school and she's his personal maid. Did I mention she now loves him and he's rather sadistic with a terrible panty fetish?

From FORTE ATROX: Kang Yurhan is handsome, rich, a little dense, and above all else lucky! But that all changes when his father's company is forced into bankruptcy. Homeless and friendless, he doesn't have a choice but to sell himself to Miss Chunja, a famous fortune teller who seems to have some plans for the poor young man...

Almost two years have passed since Ryousuke made his wish to become a beautiful girl. Although he continuously and faithfully tended the plant that was supposed to make this seemingly impossible transformation a reality, the miracle has yet to happen! To what lengths will Ryousuke go in order to make Gunma fall in love with him? Is it possible that Gunma might actually return Ryousuke’s feelings…!?

Konatsu's dream is to become a movie director. She falls in love with a popular actor, Aoi Nonomiya, and decides to confess to him upon her friends' encouragement. But...

From Taciturnity Scans:

Second-year middle school student Ayumu Kurihara changes classes and is seated next to the beautiful but strange Misuzu Tsukishima who dislikes boys. Misuzu can't get close to other people, but after being moved by Ayumu's sweet, honest personality she begins to open up to her little by little. Ayumu too is captivated by the awkwardly delicate Misuzu and the two of them become close.

V.3 (a.k.a. Second Season)
It's Shimizu Kanako's first day at an all-girls high school, and she's a little overwhelmed. Hoping to make new friends, she bumps into the odd and distant Kamei Ao, as well as her first three new friends: Aki, Rikako and Haruna. Of course, not all can be so sweet in the world of girls.

Anna entered the same high school as the person she loved. But that person is in fact her cousin, Reiji. While continuing to conceal her feelings for him, she begins to suspect that Reiji is love with Rumi, her best friend. But what is Rumi's real secret...?

From JShoujo Scans:
After three years Mimi comes back to the island where she had spent her childhood. She is greeted by her childhood friends Yousuke, Sumire and Hikari. Heartbroken in Tokyo, she has now came back to the beautiful island surrounded by the deep blue sea.
But among this four friends, friendship soon turns to love? A blue world spreads before your eyes, an unforgettable story begins.

This is the story about a girl who was named Lily by her grandfather, who hates her name because it becomes a laughing and teasing matter. Her grandfather passes away, and she comes to disbelieve miracles. One day she meets Abe, a guy who once knew her grandpa and, thanks to him and to her grandfather she learns to like her beautiful name and realizes the world is full of miracles.

Chopin and Liszt - both great composers, friends, and rivals. Liszt, after Chopin's death, Liszt remembers their meeting, their friendship, their lives together, and the music they made.

From Manga Abyss:

Hotaru managed to get in the same high school where Haruna-sensei teaches to see him again! However, on her first day there, she meets a very unpleasant guy who looks just like her beloved sensei...?

Asuka swore she'd leave the night life behind when her brother's job moved them to a new city...after all, it's hard to be a cat-burglar when you live with a detective! Despite her determination to move on, her talent for thievery hasn't gone unnoticed, and it seems her secret identity is not so secret! Approached and asked to join the group of chivalrous vigilante thieves taking the underworld by storm, Asuka has no choice but to accept...but can she keep her brother off her case?

A boy whose father fell prey to a book which drives its readers to take their own lives, a girl who tries to protect the boy from meeting a similar fate, a forensic pathologist who cannot forgive herself for the death of a girlhood friend, a mysterious used-book store - The Book Club - that only deals with books about death and despair, and a suicide which was committed in the ancient Library of Alexandria are all inexplicably connected in this unusual Korean horror story.

From ShoujoMagic:

Yori's attitude has changed. He and his twin sister, Iku, used to be inseparable as children, but lately Yori's been different -- eager to be apart from Iku. Iku worries that he hates her, but the truth is far more scandalous. Now, Yori would risk losing everything to have his little sister. Iku loves her big brother enough that she would never risk losing him, and so she'll do what it takes to keep them together... but Yori doesn't want to have her that way -- as a sister dedicated to her twin. Can Iku ever love Yori not as a brother but as a man?

Boku wa Imouto ni Koiwosuru received the Shogakukan Manga Award for shoujo manga in 2008.

Mitsuki's a high school freshman worried about her looks--or, at least, her "baby face". Until, that is, she enlists a little help from classmate Atsuki and her makeup kit. When Atsuki's finished, the transformation is complete--and breathtaking. It's also when the romantic adventures begin--a roller coaster ride of the heart that young and old are sure to enjoy.

There are 2 extra chapters in 1/2 Ceremony (1/2 series book 4).