Romance

A male to female ratio of 1:359?!

Saotome-kun is admitted into a school full of gyarus and meets a delinquent girl named Hanako Kuzuryu.
Retail:

When he came to his senses, Hirasawa Kazuki, a normal university student, found himself in possession of the body of a game’s character. Moreover, it was Harold Stokes, the story’s most hated character who was even given the title 『King of tr*sh』by the players. Myriads of landmines are just waiting for him to step on them, like death flags! Will Harold be able to clear the survival route while avoiding the countless death flags in his way?!

After a night of heavy drinking, I found myself transmigrated inside a novel as the villainous Empress Yulia, who will be executed for treason in three days.
This is a project to find a way for the workaholic empress to live, to exact her revenge and prevent treason from happening.
Will I be able to become a good and wise ruler?

The constitution of an unexpected empress.
The turbulent reign of the straightforward and gentle looking, but iron-fisted Empress Yulia.

Original Webcomic
Original Webnovel by Miraenabi

Alta is the youngest knight in history and the reincarnation of the legendary "Sword Saint". He is dispatched to the school to protect Iris, the "Sword Saint Princess" who is the next king's candidate, but "Please fight with me seriously", but Iris, who is supposed to be his escort, suddenly challenges him to a fight...!

Mao

Nanoka Kiba, a female high-school student, 8 years earlier was near death because of some supernatural circumstances. In the present, one day she find herself again in dangerous supernatural events, but this time she is saved by the mysterious Mao, a young man apparently from another dimension.

The story is set in a "land where two worlds intersect," and it centers on "a strange romance between a boy and girl who meet by fate."

Since vampires have appeared, the world has been thrown into chaos. Park Ha-yan (name meaning white) just wants to live an ordinary life, despite being born a vampire. However, with all the mix-bloods going after her, she gets swept away into the violent underworld.

A-Rank Boukensha No Slow Life summary:
Aldred, the leader of a kingdom’s A-ranked party,『Black Silver』, has accomplished the task of slaying a dragon. However, he who has pursued strength his whole life has lost sight of his goal from taking down a monster of the strongest species. As he worried about what to do next in his life, it was the scenery of Nordende that popped up in his mind; A rural village by the countryside, full of natural beauty, which he only visited once during a quest in the past.

I'm aiming to be like Haare's number one receptionist onee-san!
In a world filled with magic, from a young age, Nanari has always wanted to be a receptionist at Haare, just like that onee-san. Her parents told her she couldn't become one unless she enrolled in the kingdom's magic academy and became a top-class magic user. However, when she gets there she's surrounded by royalty and nobility. Nanari is determined to be the best amongst all the commoners! But the prince who sits beside her is always getting in her way!

The Labyrinth Raids of the Ultimate Tank ~The Tank Possessing a Rare 9,999 Endurance Skill was Expelled from the Hero Party~ summary:
Rude is a tank, known as the strongest in history. However, the Hero decided that his skills were worthless because he couldn't do anything but take damage, and threw him out of the party. His cleric friend who trusted him followed him to the remote village that Rude was forced to return to.

Our young protagonist faces the greatest challenge of his time... babysitting and rehabilitating three massive perverts. Their rich father has given him the arduous task of turning them into three young, refined ladies.

But don't sweat the details. You're just here to self-insert, right? Just pick your waifu: masochist senpai, nympho classmate, or exhibitionist kouhai.