GuessAnime.

10. Isekai wa Smartphone to Tomo ni.

When Touya Mochizuki is accidentally struck by lightning and killed, God apologizes by reviving him into a fantasy world and granting him one wish. Touya’s request? To keep his smartphone in the next world. In his second chance at life, Touya befriends many important figures, inherits the legacy of an ancient civilization, and travels around with incredible power and a harem of girls!

In Another World With My Smartphone is finished and has 12 Episodes. It is also Known as: 異世界はスマートフォンとともに。, In a Different World with a Smartphone.

9. Tensei shitara Slime Datta Ken

Corporate worker Mikami Satoru is stabbed by a random killer, and is reborn to an alternate world. But he turns out to be reborn a slime! Thrown into this new world with the name Rimuru, he begins his quest to create a world that’s welcoming to all races.

That Time I Got Reincarnated as a Slime is finished and has 24 Episodes. It is also Known as: 転生したらスライムだった件, Tensei shitara Slime Datta Ken

8. Shikkakumon no Saikyou Kenja

His strength limited by the magical crest with which he was born, Matthias, the world’s most powerful sage, decides reincarnation is necessary to become the strongest of all. Upon his rebirth as a young boy, Matthias is thrilled to discover he’s been born with the optimal crest for magical combat on his first try! Unfortunately, the world he’s been born into has abysmally poor standards when it comes to magic, and everyone thinks he’s still marked for failure! Now it’s up to Matthias to prove everyone wrong…world’s strongest sage-style!

The Strongest Sage with the Weakest Crest is finished and has 12 Episodes. It is also Known as: 失格紋の最強賢者, The Strongest Sage of Disqualified Crest, Shikkakumon no Saikyokenja

7. Mahouka Koukou no Rettousei

In the dawn of the 21st century, magic, long thought to be folklore and fairy tales, has become a systematized technology and is taught as a technical skill. In First High School, the institution for magicians, students are segregated into two groups based on their entrance exam scores: "Blooms," those who receive high scores, are assigned to the First Course, while "Weeds" are reserve students assigned to the Second Course.

Mahouka Koukou no Rettousei follows the siblings, Tatsuya and Miyuki Shiba, who are enrolled in First High School. Upon taking the exam, the prodigious Miyuki is placed in the First Course, while Tatsuya is relegated to the Second Course. Though his practical test scores and status as a "Weed" show him to be magically inept, he possesses extraordinary technical knowledge, physical combat capabilities, and unique magic techniques—making Tatsuya the irregular at a magical high school.

The Irregular at Magic High School is finished and has 26 Episodes. It is also Known as: 魔法科高校の劣等生, Mahouka Koukou no Rettousei

6. Mushoku Tensei: Isekai Ittara Honki Dasu

When a 34-year-old underachiever gets run over by a bus, his story doesn't end there. Reincarnated in a new world as an infant, Rudy will seize every opportunity to live the life he's always wanted. Armed with new friends, some freshly acquired magical abilities, and the courage to do the things he's always dreamed of, he's embarking on an epic adventure—with all of his past experience intact!

Mushoku Tensei: Jobless Reincarnation is finished and has 11 Episodes. It is also Known as: 無職転生 ～異世界行ったら本気だす～, Mushoku Tensei: Isekai Ittara Honki Dasu

5. Hachi-nan tte, Sore wa Nai deshou!

Ichinomiya Shingo, a 25-year-old man working at a firm company, while thinking of tomorrow's busy working day, goes to sleep. However, when he woke up, he found himself in a room unknown to him and realized that he is inside a 6-years-old body, taking over his body and mind. He soon learns from the memories of the boy that the boy was born as the youngest child of a poor noble family living in a back country. Having no administrative skill, he can't do anything to manage the vast land his family has. Fortunately, he is blessed with a very rare talent, the talent of magic. Unfortunately, while his talent could bring prosperity to his family, in his situation it only brought disaster. This is the story of the boy, Wendelin Von Benno Baumeister, opening his own path in a harsh world

The 8th Son? Are You Kidding Me? is finished and has 12 Episodes. It is also Known as: 八男って、それはないでしょう！, Hachi-nan tte, Sore wa Nai deshou!

4. Knight's & Magic

A genius programmer and hardcore robot otaku is reborn into a world of knights and magic, where huge robots called Silhouette Knights roar across the land! Now reborn as Ernesti Echevalier, he uses his vast knowledge of machines and programming talents to begin to make his ultimate robot. But his actions have unexpected results...?! The dreams of a robot otaku will change the world!

Knight's & Magic is finished and has 13 Episodes. It is also Known as: ナイツ&マジック, Knight's and Magic

3. Tatoeba Last Dungeon Mae no Mura no Shounen ga Joban no Machi de Kurasu Youna Monogatari

The story follows Lloyd, a budding adventurer who just wants to get stronger. His plan? Head to the capital and discover his true power, even though he grew up being considered a weakling. So Lloyd heads out from his hometown, which interestingly exists directly next to the most dangerous dungeon. He might not think of himself as strong, but he’ll soon learn that there’s even more of a difference between him and other starting adventurers.

You know, because he grew up next to a deadly dungeon. He’s much stronger than he realizes.

Suppose a Kid From the Last Dungeon Boonies Moved to a Starter Town is finished and has 12 Episodes. It is also Known as: たとえばラストダンジョン前の村の少年が序盤の街で暮らすような物語, Tatoeba Last Dungeon Mae no Mura no Shounen ga Joban no Machi de Kurasu Youna Monogatari

2. Maou Gakuin no Futekigousha: Shijou Saikyou no Maou no Shiso, Tensei shite Shison-tachi no Gakkou e Kayou

After 2000 years has passed, the ruthless demon lord has just been reincarnated! But his aptitude at an academy for nurturing candidates for demon lords is, “inept”!?Having the capability to destroy humans, elementals, and gods, after a long period of countless wars and strife, Arnos the demon lord became sick and tired of all that and longed for a peaceful world, so he decided to reincarnate to the future.However, what awaited him after his reincarnation is a world too used to peace that his descendants became too weak due to a huge weakening in magical powers.

Maou Gakuin no Futekigousha: Shijou Saikyou no Maou no Shiso, Tensei shite Shison-tachi no Gakkou e Kayou is finished and has 13 Episodes. It is also Known as: 魔王学院の不適合者 ～史上最強の魔王の始祖、転生して子孫たちの学校へ通う～, The Misfit of Demon King Academy: History's Strongest Demon King Reincarnates and Goes to School with His Descendants

1. Death March kara Hajimaru Isekai Kyousoukyoku

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 a powerful ability he possesses with limited use, he ends up wiping out an army of lizard men and becomes a high leveled adventurer. Satou decides to hide his level, and plans to live peacefully and meet new people. However, developments in the game's story, such as the return of a demon king, may cause a nuisance to Satou's plans.

Death March to the Parallel World Rhapsody is finished and has 12 Episodes. It is also Known as: デスマーチからはじまる異世界狂想曲, Death March kara Hajimaru Isekai Kyousoukyoku