| ribbons | Ribbons Data |
| rif | FRAMES Receptor Intakes File |
| riff | Resource Interchange File Format |
| rinex | Receiver Independent Exchange Format Data |
| rio | OMICRON Test Universe RIO Object |
| rir | RIR Statistics Exchange Format Data |
| rir8 | Avantes Avasoft v8 Relative Irradiance Mode Data |
| riscos | RISC OS Data |
| rit | DriveClone Data File |
| riv | CRiSP Harvest Data |
| rjt | RealJukebox Track Info Style |
| rki | Race-Keeper Video Index Data |
| rkl | VST-AU Alpha JUNO Editor License Key Data |
| rkn | Reckon Personal Plus Backup Data |
| rkp | RemoteKeys Profile Data |
| rkplr | NI REAKTOR Player Data |
| rks | SOBEK Rainfall Series Data |
| rky | SDLX Registration Key Data |
| rl | R.viewer List Data |
| rl1 | RL-1 Database Data |
| rl7 | PCAnywhere Remote Session Log |
| rld | RecLoad Definition |
| rlg | RegCleaner Language File |
| rlhead | CrazyTalk Head Data |
| rlist | PLINK Rare Genotype List File |
| rlmt | ShockLine MS46121A Ripple Limit Data |
| rlo | Reflection Desktop Layout Data |
| rlog | MPICH Log Data |
| rls | RadLight Skin Data |
| rls | SymbianOS Localization Data |
| rlt | ReliaSoft Weibull++ Template |
| rlw | ReliaSoft Weibull++ Page |
| rlx | XMetaL Author Rules Data |
| rly | Railway Operation Simulator Layout Data |
| rm2 | Hammer Reminders Data |
