| rnl | SPANS Raster Interchange Data |
| rno | PDP-10 Runoff Input Data |
| rnt | EdgeCAM Licensing Data |
| rnx | RealPlayer RNX Data |
| roc | SpaceCAD Rocket Model |
| roca | RIB Office Compressed Archive |
| rod | Siebel Report Object Design |
| rodx | Ancestry Genealogical Database |
| rodz | Ancestry Genealogical Database |
| rog | Roger 2 Input Data |
| roh | Avantes USB Spectrometer Data |
| roi | Shark ROI System Data |
| roi | Siebel Report Object Instance |
| roi | MotionTracking Regions of Interest Data |
| rok | Roku HD1000 Firmware Update |
| rol | Siebel Report Object Library |
| rom | NES ROM Image |
| rom | AMI BIOS Firmware Update |
| rom | General ROM Image |
| roo | Oracle CODASYL DBMS Database Root |
| root | HippoDraw ROOT Ntuples |
| rop | PSS/E OPF Model |
| ror | Resources of a Resource File |
| rot | STK Central Body Rotation File |
| rou | Route 66 Route Data |
| rou | EnRoute v3 Toolpath Data |
| rov | Siebel Report Object Variable |
| rox | Siebel Report Object Executable |
| roz | aSc Timetables Data |
| rp2 | RetroPlatform Player Archive |
| rp9-snapshot | RetroPlatform Snapshot Image |
| rpb | Radmin Phonebook |
| rpc | Crystal Reports RPC File |
| rpc | BillQuick Enterprise Invoice Data |
| rpc3 | NI Diadem RPC3 File |