Top 6 Anime with an overpowered reincarnated main character

Death March to the Parallel World Rhapsody is a Japanese light novel series written by Hiro Ainana. It began serialization online in 2013 on the user-generated novel publishing website Shōsetsuka ni Narō until it was acquired by Fujimi Shobo. The first volume of the Light Novel was published in March 2014.

Episodes: 12
Status: Finished Airing
Aired: Jan 11, 2018, to Mar 29, 2018
Dubbed: yes
Producers: Sotsu, AT-X, DIVE II Entertainment, Tokyo MX, Avex Pictures, BS11, Kadokawa, KLab
Studios: SILVER LINK., Connect
Source: Light novel
Genres: Adventure, Fantasy, Harem
Duration: 23 min. per ep.

Plot Summary:

In this anime, 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 levelled 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.

How Not to Summon a Demon Lord, also known as The King of Darkness Another World Story: Slave Magic is a Japanese light novel series written by Yukiya Murasaki and illustrated by Takahiro Tsurusaki. The light novels are published in English by J-Novel Club

Episodes: 22 (2 SEASONS)
Status: Finished Airing
Aired: Jul 5, 2018 to Sep 20, 2018
Dubbed: Yes
Broadcast: Thursdays at 21:30 (JST)
Producers: Sotsu, Kodansha, Half H.P Studio, AT-X, KlockWorx, DIVE II Entertainment, 81 Produce, Tokyo MX, Avex Pictures, Q-Tec, Animatic, Eswood
Studios: Ajia-Do
Source: Light novel
Genres: Comedy, Ecchi, Fantasy, Harem, Magic
Duration: 23 min. per ep.

Plot Summary: 

In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist "I am the real summon master." Takuma gets slave-turning magic used for summoned beasts cast on him by the girls― However, the peculiar ability "Magic Reflection" is invoked! The ones that were turned into slaves were the girls! Takuma was bewildered. He's the strongest magician but, he doesn't have any social skills. Panicking, the first words that came out were the ones that he used inside the game role-playing the Demon King?! "I'm amazing you say? Of course, I am. I am Diablo... The one feared as the Demon King!" This is the story of the Demon King (acting) that would soon inspire the world and his other world adventure that he plunges through with his absolute strength, raise the curtain!

That Time I Got Reincarnated as a Slime also known as TenSura or Slime Isekai is a Japanese fantasy light novel series written by Fuse, and illustrated by Mitz Vah. 

Episodes: 44 (2 SEASONS; 24 Eps SEASON 1, 12 Eps SEASON 2 Part 1, 8 Eps SEASON 2 Part 2)
Status: Ongoing -SEASON 2 Part 2
Aired: Oct 2, 2018 to Mar 19, 2019
Dubbed: Yes
Broadcast: Tuesdays at 00:00 (JST)
Producers: Lantis, Kodansha, BS11, Bandai Namco Arts, Micro Magazine Publishing
Studios: 8bit
Source: Light novel
Genres: Action, Adventure, Comedy, Demons, Magic, Fantasy
Duration: 23 min. per ep.

Plot Summary:

In the anime, "Rimuru Tempest" is the new name of a slime in a fantasy world taken by a former 37-year-old human Satou Mikami after he is killed by a passing robber. Broken free from an ordinary, stale past life, his fresh adventure in a fantasy world as a slime monster with unique abilities begins.

Arifureta: From Commonplace to World's Strongest (Japanese: ありふれた職業で世界最強, Hepburn: Arifureta Shokugyō de Sekai Saikyō) is a Japanese light novel series written by Ryo Shirakome and illustrated by Takayuki. Originally a web novel, the series has been published in print since 2015.

Episodes: 13(1SEASON)
Status: Finished Airing
Aired: Jul 8, 2019, to Oct 7, 2019
Dubbed: Yes
Broadcast: Mondays at 23:30 (JST)
Producers: AT-X, Sony Music Communications, Bushiroad, Toranoana, Hakuhodo DY Music & Pictures, Overlap, FuRyu, Bandai Namco Arts
Studios: Asread., White Fox
Source: Light novel
Genres: Action, Adventure, Harem, Fantasy
Duration: 23 min. per ep.

Summary:

Seventeen-year-old Hajime Nagumo is your average, everyday otaku. However, his simple life of pulling all-nighters and sleeping in school is suddenly turned upside down when he, along with the rest of his class, is summoned to a fantasy world! 

They're treated like heroes and tasked with the duty of saving the human race from utter extinction. But what should have been any otaku's wet dream quickly turns into Hajime's nightmare. 

While the rest of his class are blessed with godlike powers, Hajime's job, Synergist, only has a single transmutation skill. Ridiculed and bullied by his classmates for being weak, he soon finds himself in despair. Will he be able to survive in this dangerous world of monsters and demons with only a glorified blacksmith's level of strength?

Demon Lord, Retry! is a Japanese fantasy light novel series written by Kurone Kanzaki and illustrated by Kōji Ogata and Amaru Minotake. It began serialization online in 2016 on the user-generated novel publishing website Shōsetsuka ni Narō, as well as the website Hameln.

Episodes: 12 (1 SEASON)
Status: Finished Airing
Aired: Jul 4, 2019, to Sep 19, 2019
Dubbed: Yes
Studios: EKACHI EPILKA
Source: Light novel
Genres: Action, Adventure, Fantasy
Duration: 23 min. per ep.

Plot Summary:

Oono Akira, a working adult that can be found anywhere, was transported to a different world while logged into a character known as the "Demon Lord" in a game he manages. 

There, he meets a girl with a disabled leg and they begin to travel together, but there's no way that others will leave a "demon lord" with such overwhelming strengths alone. While being targeted by countries and saints that are trying to subdue the demon lord, they cause turmoil wherever they go. Demon lord on the outside, normal person on the inside, a misunderstanding type fantasy!

The Saga of Tanya the Evil, known in Japan as Youjo Senki, is a Japanese light novel series written by Carlo Zen and illustrated by Shinobu Shinotsuki. It began serialization online in 2012 on the user-generated novel publishing website Arcadia.

Episodes: 12 (1 SEASON)
Status: Finished Airing
Aired: Jan 6, 2017 to Mar 31, 2017
Dubbed: Yes
Producers: Media Factory, AT-X, Enterbrain, Sony Music Communications
Studios: Nut
Source: Light novel
Genres: Action, Military, Magic
Duration: 24 min. per ep.

Plot Summary:

On the front lines of the war, there is a little girl. Blond hair, blue eyes, and porcelain white skin, she commands her squad with a lisping voice. 

Her name is Tanya Degurechaff. But in reality, she is one of Japan's most elite salarymen, reborn as a little girl after angering a mysterious being who calls himself God. 

This little girl, who prioritizes efficiency and her own career over anything else, will become the most dangerous being amongst the sorcerers of the imperial army.