| nyl | Novapoint Vertical Alignment Data |
| nym | Sheffield Dictionary Data |
| nyt | Times Reader Article Data |
| nzl | Corel Painter Nozzle Data |
| nzn | NoteZilla Notes Data |
| nzn | RMCProfile Nitrogen Zinc Neighbours Data |
| o2s | Oracle-to-MySQL Profile Description Data |
| o3 | Ozone Messenger Program Support File |
| o3d | Google Open 3D Data |
| o8c | OCTGN Card Image |
| o8d | OCTGN Deck Data |
| o8g | OCTGN Game Definition Data |
| o8o | Mediator 5 Repository Tabs Data |
| o8s | OCTGN Set Data |
| oa | Cadence OrCAD OpenAccess Data |
| oa | OpenAccess Database |
| oab | Microsoft Outlook Offline Address Book |
| oal | Forms Design Tool Pattern License Data |
| oam | Adobe Edge Animate Widget |
| oar | HSQLDB Database |
| oas | Outlook Attachment Sniffer Data |
| oaw | OpenArchitectureWare Workflow Data |
| ob | IBM LinkWay Object |
| ob! | Orbit Downloader Unfinished File |
| ob3 | ORTIMzeit Data File |
| obc | AICON 3D Photogrammetry File |
| obd | Oracle Forms Online Help Data |
| obg | ZBrush Mesh Data |
| obi | Microsoft Outlook RSS Subscription Data |
| obj | Wavefront Object File |
