Adventure

One-In-Seven-Billion Irregular

One-Punch Man

One-Timer

Online Game: I Can Evolve Everything

Only I Know About “Leveling Up” in this World

Only Sense Online

Onna Kishi to Kemomimi no Ko

Onna Majutsushi-san, Moto no Sekai e Kaeru Tame ni Ganbarimasu

Ooparts

Orc Hero Story – Discovery Chronicles

Ore dake Chou Tensai Renkinjutsushi – Yurui Atelier Seikatsu Hajimemashita

Ore ni Tsugo ga Yosugiru machi ~Shihai sha Skill de Isekai Harem musou~

Ore no vaccine dake ga zonbi-ka shita sekai o sukueru

Ore To Seijo Ga Dekiteru Koto Ga Baretara Kono Party Wa Houkai Suru

Ore wa Akutou de wa Arimasen

Ore wa Mada, Honki wo Dashite Inai DX

Ore wa Subete o “Parry” Suru: Gyaku Kanchigai no Sekai Saikyou wa Boukensha ni Naritai

Ossan Isekai de Saikyou ni Naru: Butsuri Tokka no Kakusei-sha

Ossan no Remake Bouken Nikki ~Autocamp kara Hajimaru Isekai Mankitsu Life~

Ossan wa Isekai de Omoi wo Togeru

Other World Warrior

Others level up, I cultivate—emerging only at Great Ascension

Otherworldly Evil Monarch

Otherworldly Overnight in the Car: Outrunner PHEV

Otherworldly Skeleton Evolution

Otohime Diver

Otome Game no Heroine de Saikyou Survival

Otome Sensou

Otr of the Flame

Outo no Hazure no Renkinjutsushi – Hazure Shokugyou datta no de, Nonbiri Oten Keiei shimasu

Outo no Hazure no Renkinjutsushi: Hazure Shokukyou Datta node, Nonbiri Omise Keiei Shimasu

Overbearing Tyrant

Overgeared

Overlord of Insects

Overpowered Healer

Overpowered Sword

Pantheon of Gods

Parallel Paradise

Parasite Mage: The MMO Chronicles

Part-Time Grim Reaper