| Extension | File Description |
| .OUZ | Uncommon Files |
| .OV | Uncommon Files |
| .OV0 | Uncommon Files |
| .OV1 | Uncommon Files |
| .OV2 | GIS Files |
| .OV3 | Uncommon Files |
| .OV4 | Uncommon Files |
| .OV5 | Uncommon Files |
| .OV6 | Uncommon Files |
| .OV7 | Uncommon Files |
| .OV8 | Uncommon Files |
| .OV9 | Uncommon Files |
| .OVA | Data Files |
| .OVB | Uncommon Files |
| .OVC | Uncommon Files |
| .OVD | Uncommon Files |
| .OVE | Audio Files |
| .OVER | Uncommon Files |
| .OVF | Uncommon Files |
| .OVG | Uncommon Files |
| .OVH | Uncommon Files |
| .OVI | Uncommon Files |
| .OVJ | Uncommon Files |
| .OVK | Uncommon Files |
| .OVL | Game Files |
| .OVLDEF | Uncommon Files |
| .OVM | Uncommon Files |
| .OVN | Uncommon Files |
| .OVO | Uncommon Files |
| .OVP | Uncommon Files |
| .OVQ | Uncommon Files |
| .OVR | Vector Image Files |
| .OVS | Uncommon Files |
| .OVT | Uncommon Files |
| .OVU | Uncommon Files |
| .OVV | Uncommon Files |
| .OVW | Audio Files |
| .OVX | Uncommon Files |
| .OVY | Uncommon Files |
| .OVZ | Uncommon Files |
| .OW | Developer Files |
| .OW0 | Uncommon Files |
| .OW1 | Uncommon Files |
| .OW2 | Uncommon Files |
| .OW3 | Uncommon Files |
| .OW4 | Uncommon Files |
| .OW5 | Uncommon Files |
| .OW6 | Uncommon Files |
| .OW7 | Uncommon Files |
| .OW8 | Uncommon Files |
| .OW9 | Uncommon Files |
| .OWA | Uncommon Files |
| .OWB | Uncommon Files |
| .OWC | Database Files |
| .OWD | Uncommon Files |
| .OWE | Uncommon Files |
| .OWF | Uncommon Files |
| .OWG | Misc Files |
| .OWH | Uncommon Files |
| .OWI | Uncommon Files |
| .OWJ | Uncommon Files |
| .OWK | Uncommon Files |
| .OWL | Developer Files |
| .OWLING | Uncommon Files |
| .OWM | Misc Files |
| .OWN | Uncommon Files |
| .OWO | Uncommon Files |
| .OWP | Uncommon Files |
| .OWQ | Uncommon Files |
| .OWR | Uncommon Files |
| .OWS | Uncommon Files |
| .OWT | Uncommon Files |
| .OWU | Uncommon Files |
| .OWV | Uncommon Files |
| .OWW | Uncommon Files |
| Extension | File Description |
| .OWX | Uncommon Files |
| .OWY | Uncommon Files |
| .OWZ | Uncommon Files |
| .OX | Uncommon Files |
| .OX0 | Uncommon Files |
| .OX1 | Uncommon Files |
| .OX2 | Uncommon Files |
| .OX3 | Uncommon Files |
| .OX4 | Uncommon Files |
| .OX5 | Uncommon Files |
| .OX6 | Uncommon Files |
| .OX7 | Uncommon Files |
| .OX8 | Uncommon Files |
| .OX9 | Uncommon Files |
| .OXA | Uncommon Files |
| .OXB | Uncommon Files |
| .OXC | Uncommon Files |
| .OXD | Uncommon Files |
| .OXE | Uncommon Files |
| .OXF | Uncommon Files |
| .OXG | Uncommon Files |
| .OXH | Uncommon Files |
| .OXI | Uncommon Files |
| .OXJ | Uncommon Files |
| .OXK | Uncommon Files |
| .OXL | Uncommon Files |
| .OXM | Uncommon Files |
| .OXN | Uncommon Files |
| .OXO | Uncommon Files |
| .OXP | Uncommon Files |
| .OXPS | Page Layout Files |
| .OXQ | Uncommon Files |
| .OXR | Uncommon Files |
| .OXS | Uncommon Files |
| .OXT | Plugin Files |
| .OXU | Uncommon Files |
| .OXV | Uncommon Files |
| .OXW | Uncommon Files |
| .OXX | Uncommon Files |
| .OXY | Uncommon Files |
| .OXZ | Uncommon Files |
| .OY0 | Uncommon Files |
| .OY1 | Uncommon Files |
| .OY2 | Uncommon Files |
| .OY3 | Uncommon Files |
| .OY4 | Uncommon Files |
| .OY5 | Uncommon Files |
| .OY6 | Uncommon Files |
| .OY7 | Uncommon Files |
| .OY8 | Uncommon Files |
| .OY9 | Uncommon Files |
| .OYA | Uncommon Files |
| .OYB | Uncommon Files |
| .OYC | Uncommon Files |
| .OYD | Uncommon Files |
| .OYE | Uncommon Files |
| .OYF | Uncommon Files |
| .OYG | Uncommon Files |
| .OYH | Uncommon Files |
| .OYI | Uncommon Files |
| .OYJ | Uncommon Files |
| .OYK | Uncommon Files |
| .OYL | Uncommon Files |
| .OYM | Uncommon Files |
| .OYN | Uncommon Files |
| .OYO | Uncommon Files |
| .OYP | Uncommon Files |
| .OYQ | Uncommon Files |
| .OYR | Uncommon Files |
| .OYS | Uncommon Files |
| .OYT | Uncommon Files |
| .OYU | Uncommon Files |
| .OYV | Uncommon Files |
| .OYW | Uncommon Files |
| .OYX | Uncommon Files |
