Circle List Which Start with [O]
- O's Alliance
- O-chaxi
- O-Mars
- O-P-L
- O-Penguin (俺企鵝)
- O.N Art Works
- O.N artworks
- O.Riginal brand
- O.RIginal brand
- O.S
- O.S.I
- O.T.Kingdom
- O/BIT
- Oasis+
- OBA-Q HONPO QT
- OBAKASAN
- Obake Yashiki (おばけやしき)
- Obedient Servant
- Obisidian Order
- Object dump
- OBK
- Oblate
- OBORO (朧)
- Oboro & Tempo Gensuidou (朧&天蓬元帥堂)
- Oboro Hyakuhachishiki (朧百八式)
- OBOXO
- OBOXO.
- Obscure buds
- Obscurity Online
- OBSERVATION
- Obsession
- Obsidian Order
- Obumanjuu (おぶまんじゅう)
- OB会
- OcalCider
- OCCHOKO-CHO
- OCEAN GRAVE
- OCEANS 55
- OCEANS55
- OchiCochi
- Ochinchin-Riichi! (オチンチンリーチ!)
- OCOCO.
- OCOTA!
- OCTOBER
- Octopus Jelly
- Odamario (オダマリオ)
- ODD STAR
- ODD STAR/ジークンドー
- ODDSTAR
- Oden Soumen (おでんそうめん)
- Odenden (おでんでん)
- ODENYA (おでんや)
- ODESSA
- Odoshiro Canvas (おどしろキャンバス)
- ODΓ (exTRA)
- Oekaki Enpitsu (おえかきえんぴつ)
- Oekaki-ya (おえかき屋)
- OEPPU
- Oeuf
- OFF
- OFF LIMIT COMPANY
- Off Mode
- Off side
- OFF SIDE
- OFF(Okina Flying Factory)
- OFFICE MASHIRITO
- Office Neko (Office猫)
- Offside
- OFFTime
- OFFTime.
- OFFTime．
- OFU (Circle)
- OFUTON
- OGA
- Ogatatei (緒方亭)
- Ogawa Jinguu (小川神宮)
- OGIKUBO100W
- OguLabo
- OH
- OH MY GOSH!!
- OH MY GOSH！！
- Ohana*
- Ohanabatake (御花畑)
- Ohanabatake Typhoon (お花畑タイフーン)
- Ohigetan (尾髭丹)
- Ohkura Bekkan (大蔵別館)
- Ohoshisamadou (おほしさま堂)
- OHTADO (おおた堂)
- OI+
- Oideyasu Honpo (おいでやす本舗)
- Oill
- Oimoto (おいもと)
- OINOMORI
- OIplus
- Oishii Coffee (おいしい珈琲)
- Oishii Oniku. (おいしいお肉。)
- Oiwaidou (御祝堂)
- Ojou no Yokushitsu (お嬢の浴室)
- OK! ALL RIGHT!!
- OK!OK!
- Oka-ya (岡屋)
- Okachimentaiko Seisakushitsu (おかちめんたいこ)
- Okadatei (おかだ亭)
- Okami Kaikou (おかみかいこう)
- Okano Hajime Tei (おかのはじめ亭)
- Okarina (おかりな)
- Okashi Tai (おかし隊)
- Okatoraya (岡虎屋)
- OKAwari
- Okayama Figure Engineering (岡山フィギュア)
- Okayu Shop
- OkayuShop
- Okayushop
- Okett
- Okina Flying Factory
- OKINA FLYING FACTORY
- Okina Flying Factory(OFF)
- Okina Flying Factory・とらっくりすこ
- Okina Flying Factry
- Okina Keikaku (翁計画)
- Okina Utsuwa (大きな器)
- Okinawa Taieki Gunjinkai (沖縄体液軍人会)
- Okirakudou (おきらく堂)
- Okosama Lunch (お子様ランチ)
- OKTM
- Okuchi no Okuchi (お口の奥地)
- OLD FACTORY
- OLD UNIVERSE
- OLD UNIVERSE 出張所
- Old Weapon (おーるどうぇぽん)
- Oldgrace
- OLDLOCK
- Oldoll
- OLlVE
- OMARUMOTORS
- Omchiken (オムチキン)
- OMEGA 2-D
- OMI
- OMI*KOME
- Omiotsuke (御御御付)
- Omise!
- Omizuya (おみずや)
- OMLET
- OMNICIDE
- Omocha Kaden (玩具家電)
- OMOCHI BOX
- OMOCHIBOX
- Omochiya-san (おもちやさん)
- Omoi Ukabi Enikki (思い浮かび絵日記)
- OMOIDEHIROBA (おもいで広場)
- Omokaji Ippai Ippai (面舵いっぱいいっぱい)
- Omoshiro Burger (おもしろバーガー)
- Omoshiro Tororokonbu (おもしろとろろこんぶ)
- Omoshiro Usagi (オモシロウサギ)
- OMUTOMA
- OMYF PROJECT
- OMYFプロジェクト
- ON LIBERTY
- ON YOUR MARK
- On ざ まゆげ
- ON-SHOW (怨床)
- Onabe no Futa (御鍋ノ蓋)
- Onakasuita
- Once Only
- OnceOnly
- One and Only
- ONE HIT WONDER
- ONE NIGHT DREAM
- One Night Stand
- ONE SHOT
- One Side Factory
- One Side Factory/The Seventh Sign
- ONE VISION
- ONE VISIONS
- One Week Holiday
- ONEBUKURO
- Onece Only
- OneCours
- Oneekyou (御姉狂)
- ONEGROSS
- ONEMate
- Onemu Hormone (おねむホルモン)
- OneNightStand
- ONEONE1
- ONEONE1（WZ販売）
- ONEONE１
- OneSideFactory
- ONEVISIONS
- OneWeekHoliday
- ONE☆HALF
- ONE☆HALＦ
- Oni 69Dan (鬼69団)
- ONI.R.S
- Onigiri (Circle)
- Onigiri-ya (おにぎりや)
- Onikibitou (鬼きび党)
- ONLINE "G.NOH"
- ONLINE HEARTS (ONLINE☆HEARTS)
- ONLINE☆HEART
- Onna Kishi no Shiro (女騎士の城)
- Onnanoko Himitsu Seisan Koujou (女の子秘密生産工場)
- Onnanoko PayaPaya (女の子パヤパヤ)
- Onomatopoeia
- Onomatopoeia(オノマトピア)
- Onsoku (おんそく)
- Onsoku Ebifly (音速エビフライ)
- Onsoku Ubaguruma (音速うばぐるま)
- Oobae Toudai (オオバエ灯台)
- Ooedo Takkyubin (大江戸宅急便)
- Oogurodou (大黒堂)
- Oojinushi (おおじ主)
- Ookami to Ikiru (狼ト生キル)
- Ookii Hou ga Suki da (大きい方が好きだ)
- OOOOOM
- Oosaka Tamashii (大坂魂)
- Ootsuku Shouji (大津久商事)
- Opaque
- OPEN BOOK
- OPEN UP
- Opera (おぺら)
- Operation Box (オペレーション・ボックス)
- Operation:Novelty
- Operation：Novelty
- Opink Shougun (おピンク将軍)
- Opiumally
- Oppai Baibai (おっぱいばいばい)
- Oppi
- OPPI
- Oppore Koppore (オッポレ☆コッポレ)
- Optimist
- Opuntia
- ORACION
- Oracle Eggs
- Oracle Eggs/PINSIZE inc
- OracleEggs
- Orange
- ORANGE BRAND
- ORANGE BULLET
- Orange Canvas
- Orange Chocolat
- Orange Maru
- Orange Mill (オレンジミル)
- Orange mosquito
- Orange Opener
- Orange Peco
- Orange Peels (オレンジピールズ)
- ORANGE POP
- Orange Portfolio
- ORANGE SHABETTE
- ORANGE SHERBERT ORCHESTRA
- ORANGE SHERBET
- Orange shooteR
- ORANGE SOFT (ORANGE・SOFT)
- Orange Sunset
- Orange Tonic
- Orange Typhoon
- Orange/Splash
- OrangeBride
- OrangeCanvas
- OrangeCarry
- OrangeMaru
- Orange☆Blossom (おれんじ☆ぶろっさむ)
- ORANGE☆CHANNEL
- ORANGE☆SOFT
- ORANGE・CHANNEL
- Orbital Express
- ORBITAL EXPRESS
- Orchid Seed (オーキッドシード)
- Orcraft
- ORCSOFT
- Ore no Futegiwa (俺の不手際)
- Ore P 1-gou (Ore P 1Gou)
- Oregun (俺軍)
- Orekichi (オレキチ)
- Oremuha X (オレムハX)
- OrenG (オレンG)
- Orenjiru (おれんジル)
- Orenjiya (オレンジ屋)
- Oretachi Misnon Ikka (俺たちミスノン一家)
- Orfevre
- ORGANISE
- ORGANIX
- Orge illust
- Ori:Gin
- Orichalcum K2 (オリハルコンK2)
- ORICOMPLEX
- Oriental Lattice
- ORIFICE
- Orifice
- ORIGIN ZERO
- Origin Zero
- ORIGINAL BOX
- ORIGINAL COMPLEX
- ORIHALCON
- Orleans (おるれあんず)
- ORO
- Oronamin D (おろなみん でぃ)
- Ororiya Enpitsudo (オロリヤ鉛筆堂)
- Ort+
- Ortensia (おるてんしあ)
- Ortho-Para
- ORTO
- Orugouru (織髪郷瑠)
- Orzコミュショーズ
- Orzコミュショーズン
- OSAKANA
- Osakana Atelier
- Osakanaland
- OSAKE
- OSAMU-LEE-TIME
- OSARU no Kai (OSARUの会)
- Osaru no Noumiso (お猿の脳みそ)
- Osarusan Panic (おさるさんパニック)
- Osenbei no Mori (おせんべいの森)
- OSHABAN (オシャバン)
- OSHIIRE wonderland
- OSHIOSHIO
- Oshiruko Kan (おしるこ缶)
- Osiris (オシリス)
- OSK偶像過激団
- OSTEREi
- OS特区
- OTA
- OTA OFFICE
- Otabe Dynamite (おたべ★ダイナマイツ)
- Otabe Dynamites (おたべ・ダイナマイツ)
- OTAD
- Otafuku-tei (おたふく亭)
- Otajai (オタじゃい)
- Otaku no Youjinbou (オタクの用心棒)
- OTAKULIFE JAPAN (オタクライフJAPAN)
- OTAOFFICE
- OTAUT-R (おたうT-R)
- Otentomaru (オテント丸)
- Othello Ice (オセロアイス)
- Others Worlds
- OTNITEG
- OTN公国
- OTO
- Otochilu Cafe
- Otogi no Kuni no Soapland (おとぎの国のソープランド)
- OTOGIYA (御伽屋)
- OTOGIYA X-9 (御伽屋X-9)
- Otokojuku (おとこじゅく)
- Otome no Eden (乙女のエデン)
- OTOMEKIBUN (乙女気分)
- Otona no Guuwa (大人の寓話(大人の童話))
- Otona Shuppan (おとな出版)
- Otona Star (大人スター)
- Otonano Omochiya (Circle) (大人のおもちや)
- OTONATEIKOKU (オトナテイコク)
- OTOREKO
- OTSUMAMI
- Otukimi Koubo (おつきみ工房)
- Otukimidango (お月見団子)
- OUNO
- OUT BOY
- Out Of Base
- Out of Blue
- Out of Fuel
- OUT OF FUEL
- Out Of Sonic
- Out Rate (アウトレート)
- OUT RUNNER
- OUTER LINKAGE
- OUTLiNE
- OUTSIDER
- Ouun (桜雲)
- OVACAS
- OVACAS アベルカイン
- OVACAS/アベルカイン
- OveR
- Over Action!!
- OVER DOSE
- OVER DRIVE
- Over EAU Ball
- OVER LIMIT
- Over Step
- Over:delta (Over:Δ)
- OVERALL
- OVERALL/no reply
- OVERDOSE
- OVERDRIVE
- OverLap
- OverLord (おーばーろーど)
- Over：Δ
- OVER：△
- OVing (Oving)
- OVOPACK
- Owakari itadaketa darou ka (お解りいただけただろうか)
- Owatasha (おわた社)
- Owataセイバー
- Owen
- OWL_ACE
- OXG
- OXIDE_Lab
- OXIDEENGINE (Circle)
- Oxydan (おきし団)
- OYASUMI
- Oyasuminasai (おやすみなさい)
- Oz69
- Ozashiki (オザ式)
- Ozitan Yasan (おじたん屋さん)
- OZON DANCE
- OZONE (おぞね)
- O’hineri
- O・A・D
- O・D・A
- O・G・G
- O型ぼんのー潜水艦
- O山出版
- O沢商店
- O．RIginal brand