| ruj | Oracle Database Recovery-Unit Journal |
| ruk | Recorder 6 Rucksack Data |
| run | Runscanner Scan Result |
| rut | Novapoint Grid File |
| rvk | GnuPG Revocation Key File |
| rvm | AVEVA Plant Design Management System Model |
| rvn | RVN Data |
| rvp | CNET CatchUp Data |
| rvq | Autodesk CFD Radiation Data |
| rvw | ReviewMate Review Data |
| rvz | AVEVA Review 3D Model |
| rw3 | RapidWeaver 3 Site |
| rw5 | Carlson 2016 RAW Data |
| rwb | RefWorks Backup File |
| rwc | WAsP Regional Wind Climate |
| rwcx | Trimble SX10 Scanned Points Data |
| rwd | NRG Symphonie Logger Raw Data |
| rwf | ReFrame Workspace |
| rwf | Gaussian Read-Write File |
| rwpat | RockWorks Pattern Tables Data |
| rws | Retina Wireless Scanner |
| rx | Borland Reflex Database Driver |
| rxdoc | iZotope RX Document |
| rxf | Resco Explorer Encrypted File |
| rxh | Borland Reflex Database Help Data |
| rxn | MDL Reaction Format Data |
| rxr | Borland Reflex Database Report Data |
| rxw | eXtendable Wad Editor RXW Data |
| rzk | Red Zion Key |
| rzs | Red Zion Security Data |
| rzw | Microsoft Outlook E-Mail Rules Data |
| rzx | Fuse Input Recording Data |
| rzx | Red Zion File Crypt Encrypted Data |
| s | Thunderbird Saved Passwords Data |
| s01 | MicroStation Modification Site Resource File |