| ods | Microsoft Outlook Express 5 Mailbox Data |
| odt | MindRender Virtual Reality Explorer Kit Object |
| 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 |
| 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 |
| 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 |
| off | Geomview Binary OFF Data |
| ofl | OtsAV File List |
| ofl_en | OtsAV File List |
| ofm | Melco Embroidery Data |
| ofm | OmniForm Form Data |
| ofm | TopLevel OfficeForms Blank Form |
| ofn | Microsoft Office FileNew File |
| ofp | Origin Function Plot Theme Data |
| ofr | Microsoft SMS Offer Description Data |
| ofr | Microsoft SMS Offer File |
| ofsi | Oxygen Forensic Detective UICC Image |
