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.

Sword Magic, where a sword is manipulated using magic to freely fly in the air, cutting down enemies. Ardis is a user of this new magic art that has never been seen before throughout the entirety of the history of magic. As a mercenary, he undertakes various requests in return for remuneration, including subjugations, escorts and investigations.

On the way home from a survey request, he protects a pair of twin girls who survived their caravan being attacked by bandits, however in this world twins are considered “abominations”.

Along with the twins and a girl who accompanies him as a follower, he holds back his anger at the world which looks coldly at the twin girls due to the goddess’ intervention.

This is the story of such a swordsman called the countless swords sorcerer.

In this world, there are two types of people. Those Who have powerful "skills", and those who don't. People born with powerful skills, exterminate monsters to level up and become successful, while people without them, become failures,who are treated harshly by society. Follow the story of Fate, a guy who works as a gatekeeper, and whose only skill is gluttony, a skill that only makes him hungry.

From MangaUpdates:

A beast tamer without a familiar, Lock had been supporting his friends in an S Rank party until they finally decided to use him as a decoy and abandoned him. After a conversation with the Fenrir his party was attacking, it chose to serve him as his familiar. By using and expanding the [Mini Monster Garden], Lock gathers more and more familiars to form the strongest- and cutest- party ever. Behold, a fantasy where men and beasts go on adventures together.

A world where monsters run rampant.

A noblewoman falls from grace and loses everything after being falsely accused.

But, she started a fresh life as an 'Immortal'. She became an adventurer capable of defeating disaster-rank monsters and taking the heads off ancient dragons with a single swing of her blade. However, behind that cool exterior... beats the heart of a ridiculously over-indulgent mother!?

“What should I do, my daughters are just too cute!?”

She wields her deadly sword for the sake of motherly love! Ogres flee and dragons tremble at the sight of this overpowered adventurer!

The fantasy adventure of the Doting Mother Sword Demon begins now!

Ongoing Touhou manga from nva222 published in the official Strange Creators of Outer World magazine.

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.

"If I had a second life, wouldn't I be able to aim to become a 'hero' again?"

Solfort Enuma is a veteran soldier who has spent over sixty years training to become a [Hero]. He is an ordinary man with no talent, but he never gave up and continued to pursue his dream. One day, Solfort faced off against the [Hero] he had always admired, but his sword failed to land a single blow and he met an unrewarding end... or so he thought, but when he woke up, he found himself reincarnated as a little girl--!?

“O, Hero!” With that cliched line, Kazuya Souma found himself summoned to another world and his adventure-- did not begin. After he presents his plan to strengthen the country economically and militarily, the king cedes the throne to him and Souma finds himself saddled with ruling the entire nation! What’s more, he’s betrothed to the king’s daughter now?! In order to get the country back on its feet, Souma calls the wise, the talented, and the gifted to his side.Five people gather before the newly crowned Souma. Just what are the many talents and abilities they possess… What path will his outlook as a realist take Souma and the people of his country down? A revolutionary transferred-to-another-world administrative fantasy series starts here!

Yoishi, the owner of a bar, is disappointed with the poor food his adventurers are eating. One day, he begins to explore the cooking method, a bitter and inedible food found in the city's labyrinth, for a group of new adventurers.

A high school girl reincarnates in another world as Lily. While she occasionally reminisces about her past life, she is now known as "the Maid of the Royal Family," after helping to rear the lady who eventually married the crown prince. One day, the court magician Leonard suddenly requests that she acts as a mother for his adopted daughter Jill.

Oringinal WebComic / Original Web Novel

Olivia is picked up by a death god, Z, deep in the forest as a child and trained by him in combat for reasons unknown. One day, Z disappears, leaving behind a letter instructing Olivia to head to the Kingdom along with a sword bearing the qualities of a death god's weapon. Thus, the girl lacking in common sense, knowledge, and normalcy sets off to join the army.

Mitsuki Kou is such a feared PVP gamer that he's earned the nickname "Crim the Headhunter" in some circles. His next game to take over? "Destiny Unchain Online", a brand new VRMMO game developed by none other than Kou's father. But, no new game on release day is without its bugs - namely, Kou glitches to the middle of nowhere, and his vampire avatar is turned into a girl! A story for all of the people who through games have met new friends and aimed for the top... start!

This is the story of a young slave gladiator in an underground arena. He doesn’t know about his past or how he got to where he is, only that his name is Aegir, and that he is strong.

One day he kills the boss and escapes the arena, joining a band of mercenaries as a new recruit. During one mission, they encounter the vampire, Lucy, who slaughters the band with her inhuman strength. After learning that Aegir only knows how to kill, Lucy lets him stay at her house, educating and taking care of him.

Two years pass, and on the day of Aegir’s departure, they both exchange a promise that if Aegir becomes a king and owns the land of Erg forest, he can come and take her as his woman. Making this his life goal, Aegir set out on a journey to become a hero, a king, and found his own kingdom.

I wasn’t reborn with talent or ability, but at least my knowledge from earth allowed me to stay one step ahead in this other world.

Magic exists here, and new progress was rapidly being made in science while magic stagnated in the name of tradition. Using my earthly knowledge and not bound by the traditional thinking, I was able to do things other wizards couldn’t even imagine.

Still, inadvertently becoming an undercover professor for a mysterious secret society at the renowned Sören academy was never in my to-do list!

Following a disastrous encounter with a noble, Myne finally resolves to say goodbye to her family and friends in the lower city, changing her name to “Rozemyne” and beginning her new life as the adopted daughter of Ehrenfest’s archduke. However, her days as an archnoble in noble society are brutal, as she is put through rigorous etiquette and magic training on top of her duties as High Bishop and forewoman. It all proves too much for a weak little seven-year-old girl… Or it would have, had the High Priest not offered her the keys to the temple’s book room as a reward. If she could get her hands on those, she’d be able to read all sorts of precious books! Her name may have changed, but Rozemyne’s passion for books remains the same as she charges into a whole new world! The detailed setting expands as the printing industry grows in size. Here begins Part 3 of this biblio-fantasy for book lovers everywhere!

When an entire bus of people are summoned to another world, Souma Nagi doesn't go along with the idea of being a Hero like the rest. Thus he leaves the palace and starts his life in another world with his ability to restructure skills. Based off the Light Novel by the same name.

Kowata Makoto is an airhead with a bad sense of direction who just moved into her relative's house, but is that all? A manga about the coming of age of a witch in modern day Japan.?

...You did read the title, right?