Groups
- oppi 3
- opt 3
- orange opener 3
- ore dake ga tokusuru onsei koubou 3
- oresam 3
- oretachi sailormoon 3
- origami 3
- original complex 3
- oronamin-day 3
- orurandolu 3
- osakana.factory 3
- osameya 3
- oshisyo-san 3
- osozaki no kuruizaki 3
- ossan 3
- osu to mesu 3
- osuichi coffee-ten 3
- otama no shippo 3
- otnk 3
- otofuhonpo 3
- otokonoko heaven 3
- otokonoko tankyuu iinkai 3
- otomeza 3
- otona no marushiki 3
- otusun club 3
- ougon no seishin 3
- ourindou 3
- outflow 3
- outside hours 3
- over dynamics 3
- overall 3
- overhead 3
- oyako donburi tei 3
- oyashiki 3
- oyasumi kobe gyuu 3
- ozo 3
- p-dogs 3
- p-factory 3
- p-rhythm star 3
- p.p.p. press 3
- paci 3
- pacofic 3
- pacost. 3
- paganheart 3
- paipai purin 3
- pair bear 3
- paitoro pump 3
- pakoyume 3
- pale lilac 3
- palin 3