| od | Atari Jaguar Sound Patch |
| Mascopt Data |
| od1 | Omnis Studio Database |
| od2 | Omnis Studio Database |
| od3 | Omnis Studio Database |
| od4 | Omnis Studio Database |
| 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/CAE Binary Output Data |
| Abaqus/Explicit Output Database |
| odc | Microsoft Office Database Connection Data |
| ode | XPP ODE Unit |
| odf | ADS40 Orientation Data |
| HMI Builder Operator Display 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 |
| odoc | Synology Office Document Pointer |
| odock | ObjectDock Theme |
| odp | Actuate Analytics Parameters Data |
| odq | Transformation Extender Old Database Query |
| odr | HMI Builder Report Data |
| Ontrack Verifile Data Report |
| ods | Microsoft Outlook Express 5 Mailbox Data |
| odt | MindRender Virtual Reality Explorer Kit Object |
| OOMMF Data Table |
| Origin Dialog Theme Data |
| 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 |
| oe6 | OpenCanvas 6 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 |
| oemigaccount | Outlook Express Temporary Migration Data |
| oes | OpenCanvas 2 Event Data |
| oesavestate | OpenEmu Saved Game |
| oet | eSignal Order Entry Ticket Data |
| oetpl | Offline Explorer Template |
| ofa | Kodak OfotoNow Data |
| ofc | Altair FEKO Paging Data |
| ofd | ObjectView Form Definition Data |
| off | AquaCrop Off-season Field Data |
| Geomview Binary OFF Data |
| ofl | OtsAV File List |
| ofl_en | OtsAV File List |
| ofm | Melco Embroidery Data |
| OmniForm Form Data |
| TopLevel OfficeForms Blank Form |
| ofn | Microsoft Office FileNew File |
| ofp | Origin Function Plot Theme Data |
| ofr | Microsoft SMS Offer Description Data |
| Microsoft SMS Offer File |
| ofsi | Oxygen Forensic Detective UICC Image |
| ofv | DOpus Saved Favorites |
| ofw | TopLevel OfficeForms Form |
| ogc | Impulse Organica Model Data |
| ogex | Open Game Engine Exchange Data |
| ogf | OnkoS Graphics Data |
| ogg | Origin Graphs Data |
| oggu | Origin Unicode Graphs Data |
| ogi | OpenPBX Gateway Interface Data |
| ogl | Molden OpenGL Model |
| ogm | Origin Matrix Data |
| ogmu | Origin Unicode Matrix Data |
| ogo | Origin Graphic Object |
