| od5 | Omnis Studio Database |
| od6 | Omnis Studio Database |
| od7 | Omnis Studio Database |
| od8 | Omnis Studio Database |
| od9 | Omnis Studio Database |
| oda | AIBO ODA File |
| odat | Hopsan Optimization Data |
| odb | Abaqus/Explicit Output Database |
| ode | XPP ODE Unit |
| odf | ADS40 Orientation Data |
| odh | Odigo Messenger History Data |
| odif | Open Document Interchange Format Data |
| odl | Microsoft OneDrive Client Log |
| odlgz | Microsoft OneDrive Client Log |
| odlsent | Microsoft OneDrive Client Sent Log |
| odn | Fluke Power Analyze Database |
| odt | Origin Dialog Theme Data |
| odt | Origin Sample Curve Data |
| odu | Odigo Messenger User Data |
| odv | Ocean Data View Data |
| odx | Microsoft BizTalk Server Orchestration File |
| oe3 | OpenCanvas 3 Event Data |
| oe4 | OpenCanvas 4 Event Data |
| oe5 | OpenCanvas 5 Event Data |
| oeaccount | Windows Mail Account Data |
| oeb | Outlook Express Backup Wizard Data |
| oec | OE-Cake File |
| oecl | Open EDA Component Library Data |
| oef | IBM Optim Export Format Data |
| oes | OpenCanvas 2 Event Data |
| oet | eSignal Order Entry Ticket Data |
| oetpl | Offline Explorer Template |
| ofa | Kodak OfotoNow Data |
| ofc | Altair FEKO Paging Data |
| off | AquaCrop Off-season Field Data |