A male to female ratio of 1:359?! Saotome-kun is admitted into a school full of gyarus.

I've been reincarnated as the villainous noble Weiss from my favorite academy game, and the fate that awaits me is nothing but the worst possible ruin, with no salvation.

I absolutely have to avoid that at all costs!

Then the only way out is to gain overwhelming power that even surpasses the game's protagonist and become the strongest!

Zarmen, an adventurer who can't level up decides to retire from the adventurer business. Furthermore, in order to graduate from virginity, he decided to splurge on all the assets that I had diligently saved up since his reincarnation at a high-class brothel. The woman who appeared in front of him was the finest woman he would ever have known. Thanks to her hospitality, Zarmen fully enjoys his first time, but at that moment, his ears hear a mysterious announcement, "Impregnation confirmed.", "Level up!" "Does this mean that the more "seeding" you do, the stronger you get?"An extraordinary implantable foreign world adventure fantasy created by a bottom adventurer who has been at level 1 for many years levels up through sex!

Okabe vowed to focus on his studies in high school, but for whatever reason, the girls around him keep sending him mixed signals…

When Kirishima Ran and his classmates were transported to another world they each received an ability. However, the ability he received, [Sexual Lunatic], has caused nothing but trouble for him. His ability allows him to make any girl he comes in contact with his slave. Because of his ability, his classmates have shunned him and forced him to separate from them. With the fires of revenge burning inside his heart, Kirishima decides to overtake the class from the shadows. One by one he turns his classmates into slaves and fill his desires.

A human boy name Light is kicked out from the adventurer party called the “Race Union(gathering of races)” by his trusted comrades.

Lucas has a hard life. In his mid-thirties, a mixture of failures has left him old and crippled, playing pack mule to a couple of young adventures.

Then one day, he pulls a magic sword from a stone that tells him he has been chosen to become a hero. Given a youthful form, Lucas must use the power of the sword to vanquish evil and attain a massive harem.

Before you ask, it’s not isekai because he’s been in this world from day one. It is wish fulfillment, though, so in the end it’s basically the same thing.

Meet the Evil King Valt, ruler of the Continent of Darkness. After being defeated by a group of heroes, he was reborn as a human, with his powers intact!

"I'll start over in this world. And this time the whole world will be mine!"

Valt garners the attention of the elite adventurer Iris. With Iris as his guardian, he enrolls at the Royal Adventurer Training School and immediately surpasses his seniors with his abnormal power! In an unprecedented move, this maverick is designated "level 0." He goes on to employ his talents as an Evil King to great effect, dominating the new world he finds himself in...

From LHtranslation :

In a certain world, there was someone who excelled in magic combat, people called him 『Sage』. Seeking the strongest combat art, he devoted himself to research every magic and combat arts in existence. And the conclusion he arrived at was very cruel, 『My body is not fit for magic combat』. Yet he didn’t give up. He sealed his own soul with a magic art, and was reborn in a far-off future. And the magic theory in the completely changed world he saw there was of unbelievably low level.

A boy named Atsumu was branded as "useless" by his famous sisters and banished from his entertainment-industry family. However, hidden within him was an extraordinarily talented "behind-the-scenes support" skill that neither he nor his family had noticed! After transferring schools, Atsumu is now determined to live a normal life, but as he crosses paths with talented entertainers—VTubers, idols, and models—his natural ability starts to shine, making him their indispensable support. They can't help but adore him, turning his simple wish for normality into a showbiz underdog success story!

Ao Sato is accidentally swapped with himself in a parallel world with a male/female ratio of 1:39.

He finds a kind family and lovely women at the place where he was switched.

Seeing the outside of these women, he's relieved to see that the number of men and women has changed, but not much else.

However, their inner lives are filled with conflicts and troubles.

Kotesashi Kouyou is the protagonist who possesses outstanding skill as a masseur. He aspires to become a sports doctor and wants to get scholarship in medical school. Starting spring, he will attend the high school attached to Seiwa University, a sports powerhouse. Since his family is not wealthy, he has to work as a hostel manager where he is allowed to stay in order to pay for his school expenses, however, there he encounters high school girl athletes with various problems. Kotesashi's job is to take care of them physically and mentally, as well as being the hostel manager. School girls from sports clubs and massages! All this will start a life full of intense excitement in the dormitories!

A romantic comedy about Nagi going to a meeting with her real parents, and about Erika, who is tormented by an unwanted engagement!

Unemployed 19-year-old Kazuma has been summoned to Asagiri Island, rumored to be home to long lost pirate treasure. He ends up working as an odd-job man at Umine Inn, a traditional Japanese café with women-only lodgings and a host of eccentric yet beautiful women.

"Late at night, alone on my bed, your voice was the only thing that saved me. I want to talk to you again. There's something I want to say."

Without knowing her real name or face, Yamabuki Arisu, a second-year high school student, was looking for a girl named "Apollo'' who was a livestreamer. However, one day, Arisu gets a clue about Apollo from the broadcast club of the high school where she is going. There were 4 beautiful girls who dreamed of "getting a job related to voice"!! Who is Apollo? What will happen to the dreams of the four people? A cute yet hard-working success romantic comedy begins here!!

Standing at the crossroads of life; the important choices - “Flags”. Hatate Souta, a young man who can see these flags, transferred to “Hatagaya Academy”, a prestigious school in the metropolitan area. Not only does he meet beautiful girls in his busy school life, he even goes as far as living with them under the same roof! Surrounded by these flags, this enviable romantic comedy begins!

The protagonist along with his step-mother, and 2 step-sisters are summoned into another world where demi-humans are the rulers as saviors, but its not to fight against a demon lord, its to fight an Undead Apocalypse monsters called "Dead Mell" that have overrun the world and that can only be killed by using weapons made with holy silver.

For that, a familia is made (group of 4 people) with them being the swordmaster that uses the holy sword, the guardian that uses the power of earth to protect, the healer that use the power of water to heal and the black mage that uses the power of fire to destroy.
The role of the guardian, the mage and the healer is to support the swordmaster that can only kill the monsters.

But to use magic powers one must offer part of your being as a sacrifice to form a contract with spirits, and the higher the sacrifice, the higher the power. Now they must choose who are the 3 that need to sacrifice part of their bodies to gain power and who will wield the holy sword.

Kou Kousaka is an ordinary salaryman working overtime in a black company when a totally unprecedented event happens: he dies and is sent to another world.

Unlike those other isekai novels where the main character decides to be a hero or a demon lord, Koko here doesn’t care for any of that. The isekai system rewards his lack of choice with several powers which have never been seen before: the ability to store items in a limitless inventory, immediately dismantle them into materials, and then use them to create something new.

How will our completely unique hero survive in this new world?

From MangaHelpers:
29-year-old programmer Suzuki Ichirou finds himself transported into a fantasy RPG. Within the game, he's a 15-year-old named Satou. At first he thinks he's dreaming, but his experiences seem very real. Due to his use of a 3-time-use special power (meteor shower), he ends up wiping out an army of lizardmen and becoming very high level. He hides his level and plans to live peacefully and meet new people, though developments in the game story (like the return of a demon king) might get in his way.

I killed the player.

He was a real son of a bitch…

He loved me too much and was a sociopath.

Now that I'm back in time, I'll kill him before being manipulated again and save the harem's girls who will help me win the video game's scenario!