| resw | Microsoft Windows Resources Data |
| reu | C64 REU Image |
| rev | Workshare Synergy REV Data |
| revinp | OnScale Review Input Data |
| rew | MRMC State Rewards Data |
| rewi | MRMC Impulse Rewards Data |
| rex | 4D Database Client Local Data |
| rex | Oracle Database Report Definition Data |
| rf1 | Retirement Forecast Data |
| rf5 | Tektronix RFXpress RF5 Record Data |
| rfa | Autodesk Revit Family File |
| rfb | RoboForm Bookmark File |
| rfc | RoboForm Contact File |
| rfd | RockFlow Simulation Data |
| rfe | RockFlow Log |
| rff | Roproc Format File Data |
| rfg | iNTEGRATOR Data |
| rfh | iNTEGRATOR Householding Data |
| rfi | SPEFO Filtered Data |
| rfl | RISAFloor Analysis Data |
| rfl8 | Avantes Avasoft v8 Reflectance Mode Data |
| rflw | Adobe Edge Reflow Data File |
| rfn | RoboForm Safenote File |
| rfo | RoboForm Option File |
| rfo | RockFlow Results Data |
| rfp | RoboForm PassCard File |
| rfq | RoboForm SearchCard File |
| rfr | Adobe Photoshop Frame Filter |
| rfs | RealFlow Script |
| rfs | Samsung RFS Image |
