| | On The Up (Mazooma) (Scorpion 4) (set 2) (clone of: sc4onup) | 1969 | BFM | sc4onupa | | 0.00 |
 | One + Two | 1997 | Barko | onetwo | Puzzle / Match *Mature* | 0.00 |
| One + Two (earlier) (clone of: onetwo) | 1997 | Barko | onetwoe | | 0.00 |
 | One Shot One Kill | 1996 | Promat | oneshot | Shooter / Gun | 6.87 |
 | Oni - The Ninja Master (Japan) (clone of: metmqstr) | 1995 | Banpresto / Pandorabox | nmaster | Fighter / Versus Co-op | 0.00 |
| | Only Fools & Horses (Bellfruit) (set 1) (Scorpion 2/3) | 1969 | BFM | sc2ofool | | 0.00 |
| | Only Fools & Horses (Bellfruit) (set 2) (Scorpion 2/3) (clone of: sc2ofool) | 1969 | BFM | sc2ofool1 | | 0.00 |
| | Only Fools & Horses (Bellfruit) (set 3) (Scorpion 2/3) (clone of: sc2ofool) | 1969 | BFM | sc2ofool2 | | 0.00 |
| | Only Fools & Horses (Bellfruit) (set 4) (Scorpion 2/3) (clone of: sc2ofool) | 1969 | BFM | sc2ofool3 | | 0.00 |
| | Only Fools & Horses (Bellfruit) (set 5) (Scorpion 2/3) (clone of: sc2ofool) | 1969 | BFM | sc2ofool4 | | 0.00 |
 | Onna Sansirou - Typhoon Gal (set 1) | 1985 | Taito | onna34ro | Fighter / Versus | 8.00 |
| Onna Sansirou - Typhoon Gal (set 2) (clone of: onna34ro) | 1985 | Taito | onna34roa | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 1) | 1969 | Bwb / Barcrest | m4oadrac | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 2) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__a | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 3) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__b | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 4) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__c | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 5) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__d | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 6) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__e | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 7) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__f | | 0.00 |
| | Ooh Aah Dracula (Barcrest) (MPU4) (set 8) (clone of: m4oadrac) | 1969 | Bwb / Barcrest | m4oadrac__g | | 0.00 |
