arcade ：Onliner Touch Party

arcade ：Onna Sanshirou - Typhoon Gal (bootleg)

arcade ：Open 5 Cards

arcade ：Opa Opa (Rev A, unprotected)

arcade ：Konami's Open Golf Championship (ver EAD)

arcade ：2 On 2 Open Ice Challenge (rev 1.2A)

arcade ：Open Mahjong (Japan)

arcade ：Operation Tiger (Ver 2.10 O)

arcade ：Operation Tiger (Ver 2.09 J)

arcade ：Operation Tiger Second Mission (Ver 2.02 J)

arcade ：Operation Wolf 3 (Japan)

arcade ：Operation Wolf 3 (US)

arcade ：Operation Wolf (World, rev 2, set 2)

arcade ：Operation Bear (bootleg of Operation Wolf)

arcade ：Operation Wolf (Japan, rev 2)

arcade ：Operation Wolf (Japan, SC)

arcade ：Operation Wolf (Japan, prototype)

arcade ：Operation Wolf (US, rev 2)

arcade ：Orange Club - Maru-hi Ippatsu Kaihou (Japan 880221)

arcade ：Orbatak (prototype)

arcade ：Orchid Mist (0100849V, NSW/ACT)

arcade ：Orchid Mist (0101241V, New Zealand)

arcade ：Ordyne (Japan)

arcade ：Ordyne (Japan, English Version)

arcade ：Orius (ver UAA)

arcade ：Oriental Legend 2 (V101, Oversea)

arcade ：Xiyou Shi E Zhuan 2 (V101, China)

arcade ：Saiyuu Shakuyakuden 2 (V101, Japan)

arcade ：Oriental Legend 2 (V103, Oversea)

arcade ：Xiyou Shi E Zhuan 2 (V103, China)

arcade ：Saiyuu Shakuyakuden 2 (V103, Japan)

arcade ：Xiyou Shi E Zhuan 2 (V104, China)

arcade ：Saiyuu Shakuyakuden 2 (V104, Japan)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 105, Korean Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 105, Taiwanese Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 111, Chinese Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 111, Korean Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 111, Taiwanese Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 112, Chinese Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. ???, Chinese Board)

arcade ：Oriental Legend / Xiyou Shi E Zhuan (ver. 112)

arcade ：OutRunners (Japan)

arcade ：OutRunners (US)

arcade ：Oscar (0100348V, NSW/ACT)

arcade ：Psycho-Nics Oscar (World revision 0, bootleg)

arcade ：Psycho-Nics Oscar (Japan revision 1)

arcade ：Psycho-Nics Oscar (Japan revision 2)

arcade ：Psycho-Nics Oscar (US)

arcade ：Disco Mahjong Otachidai no Okite (Japan)

arcade ：Operation Thunderbolt (Japan)

arcade ：Operation Thunderbolt (Japan, SC)

arcade ：Operation Thunderbolt (World)

arcade ：Operation Thunderbolt (US, rev 1)

arcade ：Operation Thunderbolt (US)

arcade ：Off the Wall (Sente) (10/16/84)

arcade ：Mahjong Ougon no Hai (Japan bootleg set 1, medal)

arcade ：Mahjong Ougon no Hai (Japan bootleg set 2, medal)

arcade ：Mahjong Ougon no Hai (Japan bootleg set 3, medal)

arcade ：The Outfoxies (Korea?)

arcade ：The Outfoxies (Japan, OU1)