| Extension | File Description |
| .OC2 | Uncommon Files |
| .OC3 | Uncommon Files |
| .OC4 | Uncommon Files |
| .OC5 | Uncommon Files |
| .OC6 | Uncommon Files |
| .OC7 | Uncommon Files |
| .OC8 | Uncommon Files |
| .OC9 | Uncommon Files |
| .OCA | Developer Files |
| .OCB | Uncommon Files |
| .OCC | Uncommon Files |
| .OCCSAN | Uncommon Files |
| .OCD | Uncommon Files |
| .OCE | Settings Files |
| .OCEN | Uncommon Files |
| .OCF | Uncommon Files |
| .OCG | Uncommon Files |
| .OCH | Uncommon Files |
| .OCI | Raster Image Files |
| .OCJ | Uncommon Files |
| .OCK | Uncommon Files |
| .OCL | Uncommon Files |
| .OCM | Uncommon Files |
| .OCN | Uncommon Files |
| .OCO | Uncommon Files |
| .OCP | Uncommon Files |
| .OCQ | Uncommon Files |
| .OCR | Text Files |
| .OCS | Uncommon Files |
| .OCSP | Uncommon Files |
| .OCT | 3D Image Files |
| .OCTOPUSFON | Uncommon Files |
| .OCU | Uncommon Files |
| .OCV | Uncommon Files |
| .OCW | Uncommon Files |
| .OCX | Developer Files |
| .OCY | Uncommon Files |
| .OCZ | Uncommon Files |
| .OC_ | Uncommon Files |
| .OD0 | Uncommon Files |
| .OD1 | Uncommon Files |
| .OD2 | Uncommon Files |
| .OD3 | Uncommon Files |
| .OD4 | Uncommon Files |
| .OD5 | Uncommon Files |
| .OD6 | Uncommon Files |
| .OD7 | Uncommon Files |
| .OD8 | Uncommon Files |
| .OD9 | Uncommon Files |
| .ODA | Uncommon Files |
| .ODB | Database Files |
| .ODC | Data Files |
| .ODCCUBEFIL | Uncommon Files |
| .ODCDATABAS | Uncommon Files |
| .ODCNEWFILE | Uncommon Files |
| .ODCTABLEFI | Uncommon Files |
| .ODD | Uncommon Files |
| .ODDS | Uncommon Files |
| .ODE | Uncommon Files |
| .ODF | Game Files |
| .ODFT | Data Files |
| .ODG | Vector Image Files |
| .ODH | Uncommon Files |
| .ODI | Raster Image Files |
| .ODIF | Text Files |
| .ODJ | Uncommon Files |
| .ODK | Uncommon Files |
| .ODL | Uncommon Files |
| .ODM | Text Files |
| .ODMP | Uncommon Files |
| .ODN | Uncommon Files |
| .ODO | Uncommon Files |
| .ODOCK | Uncommon Files |
| .ODP | Data Files |
| .ODQ | Uncommon Files |
| Extension | File Description |
| .ODR | Uncommon Files |
| .ODS | Misc Files |
| .ODS# | Uncommon Files |
| .ODT | Text Files |
| .ODU | Uncommon Files |
| .ODV | Uncommon Files |
| .ODW | Uncommon Files |
| .ODX | Uncommon Files |
| .ODY | Uncommon Files |
| .ODZ | Uncommon Files |
| .OE0 | Uncommon Files |
| .OE1 | Uncommon Files |
| .OE2 | Uncommon Files |
| .OE3 | Uncommon Files |
| .OE4 | Uncommon Files |
| .OE5 | Uncommon Files |
| .OE6 | Uncommon Files |
| .OE7 | Uncommon Files |
| .OE8 | Uncommon Files |
| .OE9 | Uncommon Files |
| .OEA | Uncommon Files |
| .OEB | Backup Files |
| .OEC | Uncommon Files |
| .OED | Uncommon Files |
| .OEE | Uncommon Files |
| .OEF | Uncommon Files |
| .OEG | Uncommon Files |
| .OEH | Uncommon Files |
| .OEI | Uncommon Files |
| .OEJ | Uncommon Files |
| .OEK | Uncommon Files |
| .OEL | Uncommon Files |
| .OEM | Data Files |
| .OEN | Uncommon Files |
| .OEO | Uncommon Files |
| .OEP | Uncommon Files |
| .OEQ | Uncommon Files |
| .OER | Uncommon Files |
| .OES | Uncommon Files |
| .OET | Uncommon Files |
| .OEU | Uncommon Files |
| .OEV | Uncommon Files |
| .OEW | Uncommon Files |
| .OEX | Plugin Files |
| .OEY | Uncommon Files |
| .OEZ | Uncommon Files |
| .OF | Uncommon Files |
| .OF0 | Uncommon Files |
| .OF1 | Uncommon Files |
| .OF2 | Uncommon Files |
| .OF3 | Uncommon Files |
| .OF4 | Uncommon Files |
| .OF5 | Uncommon Files |
| .OF6 | Uncommon Files |
| .OF7 | Uncommon Files |
| .OF8 | Uncommon Files |
| .OF9 | Uncommon Files |
| .OFA | Uncommon Files |
| .OFASTER | Uncommon Files |
| .OFB | Uncommon Files |
| .OFC | Data Files |
| .OFD | Uncommon Files |
| .OFE | Uncommon Files |
| .OFF | 3D Image Files |
| .OFFENSE | Uncommon Files |
| .OFFICES | Uncommon Files |
| .OFG | Uncommon Files |
| .OFH | Uncommon Files |
| .OFI | Uncommon Files |
| .OFJ | Uncommon Files |
| .OFK | Uncommon Files |
| .OFL | Text Files |
| .OFM | Data Files |
| .OFN | Uncommon Files |
| .OFO | Uncommon Files |
