Underestimated/Overpowered Protagonist in fantasy/isekai (PART 1)
Manga
Basically a list for power fantasy.
(PART 2) https://myanimelist.net/stacks/48365
Mistreated/detested lead characters in fantasy/isekai
https://myanimelist.net/stacks/36917
Lead Characters misunderstood/adored by people around them in fantasy/isekai
https://myanimelist.net/stacks/36957
Adventurer party/Hero's Party in fantasy/isekai
https://myanimelist.net/stacks/36966
Slave Companion in Fantasy/Isekai
https://myanimelist.net/stacks/38526
(PART 2) https://myanimelist.net/stacks/48365
Mistreated/detested lead characters in fantasy/isekai
https://myanimelist.net/stacks/36917
Lead Characters misunderstood/adored by people around them in fantasy/isekai
https://myanimelist.net/stacks/36957
Adventurer party/Hero's Party in fantasy/isekai
https://myanimelist.net/stacks/36966
Slave Companion in Fantasy/Isekai
https://myanimelist.net/stacks/38526
Ichioku-nen Button wo Renda shita Ore wa, Kizuitara Saikyou ni Natteita: Rakudai Kenshi no Gakuin Musou
I Kept Pressing the 100-Million-Year Button and Came Out on Top: The Unbeatable Reject Swordsman

Manga, ? vol, 2020
Me:-
Author:7
Arifureta Shokugyou de Sekai Saikyou
Arifureta: From Commonplace to World's Strongest

Manga, ? vol, 2016
Me:-
Author:-
Adapted from a recommended Light Novel series.
Saikyou Degarashi Ouji no Anyaku Teii Arasoi
The Insipid Prince's Furtive Grab for the Throne

Manga, ? vol, 2019
Me:-
Author:-
Adapted from a Light Novel series.
Magical★Explorer: Eroge no Yuujin-Chara ni Tensei shita kedo, Game Chishiki Tsukatte Jiyuu ni Ikiru
Magical Explorer: Reborn as a Side Character in a Fantasy Dating Sim

Light Novel, ? vol, 2019
Me:-
Author:8
Recommended Light Novel series. Has a Manga adaption. ( https://myanimelist.net/manga/129305 )
Shinja Zero no Megami-sama to Hajimeru Isekai Kouryaku
Full Clearing Another World under a Goddess with Zero Believers

Light Novel, ? vol, 2019
Me:-
Author:9
Recommended Light Novel series. Has a Manga adaption. ( https://myanimelist.net/manga/130508 )

Manga, ? vol, 2022
Me:-
Author:7
Shinjiteita Nakama-tachi ni Dungeon Okuchi de Korosarekaketa ga Gift "Mugen Gacha" de Level 9999 no Nakama-tachi wo Te ni Irete Moto Party Member to Sekai ni Fukushuu & "Zamaa!" Shimasu!
Backstabbed in a Backwater Dungeon: My Party Tried to Kill Me, But Thanks to an Infinite Gacha I Got LVL 9999 Friends and Am Out for Revenge

Manga, ? vol, 2021
Me:-
Author:8
Tensei shitara Saikyoushu-tachi ga Sumau Shima deshita. Kono Shima de Slow Life wo Tanoshimimasu
Living a Laid-Back Second Life on the Island of the Strongest Species

Manga, ? vol, 2022
Me:-
Author:6
Rettougan no Tensei Majutsushi: Shiitagerareta Motoyuusha wa Mirai no Sekai wo Yoyuu de Ikinuku
The Reincarnation Magician of the Inferior Eyes.

Manga, 16 vol, 2018
Me:-
Author:7
Rettoujin no Makentsukai: Skill Board wo Kushi shite Saikyou ni Itaru
The Inferior Magic Swordsman

Manga, ? vol, 2020
Me:-
Author:7

Manga, ? vol, 2016
Me:-
Author:8
Adapted from a recommended Light Novel series.
Isekai Teni shita node Cheat wo Ikashite Mahou Kenshi Yaru Koto ni Suru
I Think I'll Cheat to Become a Spellsword in Another World

Manga, ? vol, 2020
Me:-
Author:7
Yurufuwa Nouka no Mojibake Skill: Isekai de Catalog Tsuuhan Yattemasu
Cheat Mode Farming in Another World

Manga, ? vol, 2019
Me:-
Author:7

Manga, ? vol, 2019
Me:-
Author:8
Lv2 kara Cheat datta Motoyuusha Kouho no Mattari Isekai Life
Chillin' in Another World with Level 2 Super Cheat Powers

Manga, ? vol, 2019
Me:-
Author:-
Tensei shitara Slime Datta Ken
That Time I Got Reincarnated as a Slime

Manga, ? vol, 2015
Me:-
Author:8
Adapted from a recommended Light Novel series.

Light Novel, ? vol, 2012
Me:-
Author:8
Recommended Light Novel series. Has a Manga & Anime adaptions.
Ore dake Fuguu Skill no Isekai Shoukan Hangyakuki: Saijaku Skill "Kyuushuu" ga Subete wo Nomikomu made
I'm the Only One with Unfavorable Skills, Isekai Summoning Rebellion

Manga, ? vol, 2022
Me:-
Author:7

Manga, ? vol, 2019
Me:-
Author:-

Manga, ? vol, 2018
Me:-
Author:-
Suterareta Tensei Kenja: Mamono no Mori de Saikyou no Daima Teikoku wo Tsukuriageru
The Abandoned Reincarnation Sage

Manga, 8 vol, 2020
Me:-
Author:8
Saikyou Onmyouji no Isekai Tenseiki: Geboku no Youkai-domo ni Kurabete Monster ga Yowasugirunda ga
The Reincarnation of the Strongest Exorcist in Another World: Monsters Can't Match my Youkai!

Manga, ? vol, 2020
Me:-
Author:-
Kizoku Tensei: Megumareta Umare kara Saikyou no Chikara wo Eru
Noble Reincarnation: Born Blessed, So I'll Obtain Ultimate Power

Manga, ? vol, 2019
Me:-
Author:8
Sokushi Cheat ga Saikyou sugite, Isekai no Yatsura ga Marude Aite ni Naranai n desu ga. ΑΩ
My Instant Death Ability Is So Overpowered, No One in This Other World Stands a Chance Against Me! —AΩ—

Manga, ? vol, 2018
Me:-
Author:7

Manga, ? vol, 2019
Me:-
Author:7
Shikkakumon no Saikyou Kenja: Sekai Saikyou no Kenja ga Sarani Tsuyokunaru Tame ni Tensei Shimashita
The Strongest Sage with the Weakest Crest

Manga, ? vol, 2017
Me:-
Author:-

Manga, ? vol, 2018
Me:-
Author:5

Manga, ? vol, 2021
Me:-
Author:-
Senken no Majutsushi to Yobareta Kenshi
The Swordsman Dubbed the Sorcerer of Countless Swords

Manga, ? vol, 2018
Me:-
Author:7
Tensei Kizoku no Isekai Boukenroku: Jichou wo Shiranai Kamigami no Shito
Chronicles of an Aristocrat Reborn in Another World

Manga, ? vol, 2018
Me:-
Author:7
Kujibiki Tokushou: Musou Harem-ken
Grand Prize: Unrivalled Harem Ticket

Manga, ? vol, 2018
Me:-
Author:6
Hazure Skill "Kage ga Usui" wo Motsu Guild Shokuin ga, Jitsu wa Densetsu no Ansatsusha
Hazure Skill: The Guild Member with a Worthless Skill Is Actually a Legendary Assassin

Manga, ? vol, 2019
Me:-
Author:-
Sekai ni Hitori, Zenzokusei Mahou no Tsukaite
The Only in the World, Omnipotent Wizard

Manga, ? vol, 2022
Me:-
Author:7
Tsuihou no Kenja, Sekai wo Shiru: Osananajimi Yuusha no Atsuryoku kara Nigete Jiyuu ni Natta Ore
A Banished Sage's Progress to Discovering the World: The Story of What Happened When I Freed Myself from My Childhood Friend

Manga, ? vol, 2021
Me:-
Author:-

Manga, ? vol, 2018
Me:-
Author:-
"Honyaku" no Sainou de Ore dake ga Sekai wo Kaihen Dekiru Ken: Hazure Sainou "Honyaku" de Kizukeba Sekai Saikyou ni Nattemashita
Only My Undesirable Translation Talent Can Change the World

Manga, 4 vol, 2022
Me:-
Author:7

Manga, 5 vol, 2021
Me:-
Author:-
Botsuraku Yotei no Kizoku dakedo, Hima Datta kara Mahou wo Kiwametemita @comic
I'm a Noble on the Brink of Ruin, So I Might as Well Try Mastering Magic

Manga, ? vol, 2020
Me:-
Author:-