| Extension | File Description |
| .RSD | Database Files |
| .RSE | Uncommon Files |
| .RSF | Data Files |
| .RSG | Uncommon Files |
| .RSH | Uncommon Files |
| .RSI | Uncommon Files |
| .RSJ | Uncommon Files |
| .RSK | Uncommon Files |
| .RSL | Uncommon Files |
| .RSM | Data Files |
| .RSML | Uncommon Files |
| .RSN | Uncommon Files |
| .RSO | Uncommon Files |
| .RSOUND | Uncommon Files |
| .RSP | Data Files |
| .RSQ | Uncommon Files |
| .RSR | Raster Image Files |
| .RSRC | Developer Files |
| .RSRT | Uncommon Files |
| .RSS | Web Files |
| .RST | Text Files |
| .RSTRNT | Uncommon Files |
| .RSU | Uncommon Files |
| .RSV | Uncommon Files |
| .RSW | Data Files |
| .RSX | Uncommon Files |
| .RSY | Uncommon Files |
| .RSZ | Uncommon Files |
| .RS_ | Uncommon Files |
| .RT | Web Files |
| .RT$ | Uncommon Files |
| .RT0 | Uncommon Files |
| .RT1 | Uncommon Files |
| .RT2 | Uncommon Files |
| .RT3 | Uncommon Files |
| .RT4 | Uncommon Files |
| .RT5 | Uncommon Files |
| .RT6 | Uncommon Files |
| .RT7 | Uncommon Files |
| .RT8 | Uncommon Files |
| .RT9 | Uncommon Files |
| .RTA | Uncommon Files |
| .RTAB | Uncommon Files |
| .RTB | Uncommon Files |
| .RTC | Misc Files |
| .RTD | Text Files |
| .RTE | Compressed Files |
| .RTF | Text Files |
| .RTFD | Text Files |
| .RTFENX | Uncommon Files |
| .RTG | Uncommon Files |
| .RTH | Uncommon Files |
| .RTI | Uncommon Files |
| .RTJ | Uncommon Files |
| .RTK | Uncommon Files |
| .RTL | Uncommon Files |
| .RTLIST | Uncommon Files |
| .RTM | Audio Files |
| .RTMDL | Uncommon Files |
| .RTN | Uncommon Files |
| .RTO | Uncommon Files |
| .RTP | Data Files |
| .RTPI | Uncommon Files |
| .RTPL | Uncommon Files |
| .RTQ | Uncommon Files |
| .RTR | Uncommon Files |
| .RTS | Audio Files |
| .RTSP | Uncommon Files |
| .RTT | Uncommon Files |
| .RTTTL | Uncommon Files |
| .RTU | Uncommon Files |
| .RTV | Uncommon Files |
| .RTW | Uncommon Files |
| .RTWKS | Uncommon Files |
| .RTX | Text Files |
| Extension | File Description |
| .RTY | Uncommon Files |
| .RTZ | Uncommon Files |
| .RT_ | Uncommon Files |
| .RU | Developer Files |
| .RU0 | Uncommon Files |
| .RU1 | Uncommon Files |
| .RU2 | Uncommon Files |
| .RU3 | Uncommon Files |
| .RU4 | Uncommon Files |
| .RU5 | Uncommon Files |
| .RU6 | Uncommon Files |
| .RU7 | Uncommon Files |
| .RU8 | Uncommon Files |
| .RU9 | Uncommon Files |
| .RUA | Uncommon Files |
| .RUB | Uncommon Files |
| .RUBY | Uncommon Files |
| .RUC | Uncommon Files |
| .RUD | Uncommon Files |
| .RUE | Uncommon Files |
| .RUF | System Files |
| .RUG | Uncommon Files |
| .RUH | Uncommon Files |
| .RUI | Uncommon Files |
| .RUJ | Uncommon Files |
| .RUK | Uncommon Files |
| .RUL | Developer Files |
| .RULER | Uncommon Files |
| .rules | Uncommon Files |
| .RUM | Uncommon Files |
| .RUMMY | Uncommon Files |
| .RUN | Executable Files |
| .RUNNER | Uncommon Files |
| .RUNQ | Uncommon Files |
| .RUO | Uncommon Files |
| .RUP | Uncommon Files |
| .RUQ | Uncommon Files |
| .RUR | Uncommon Files |
| .RUS | Uncommon Files |
| .RUSH | Uncommon Files |
| .RUSHERS | Uncommon Files |
| .RUT | Uncommon Files |
| .RUU | Uncommon Files |
| .RUV | Uncommon Files |
| .RUW | Uncommon Files |
| .RUX | Uncommon Files |
| .RUY | Uncommon Files |
| .RUZ | Uncommon Files |
| .RV | Video Files |
| .RV0 | Uncommon Files |
| .RV1 | Uncommon Files |
| .RV2 | Data Files |
| .RV3 | Data Files |
| .RV4 | Uncommon Files |
| .RV5 | Uncommon Files |
| .RV6 | Uncommon Files |
| .RV7 | Uncommon Files |
| .RV8 | Uncommon Files |
| .RV9 | Uncommon Files |
| .RVA | Uncommon Files |
| .RVB | Uncommon Files |
| .RVC | Uncommon Files |
| .RVD | Uncommon Files |
| .RVE | Uncommon Files |
| .RVF | Uncommon Files |
| .RVG | Uncommon Files |
| .RVH | Uncommon Files |
| .RVI | Uncommon Files |
| .RVJ | Uncommon Files |
| .RVK | Uncommon Files |
| .RVL | Video Files |
| .RVM | Uncommon Files |
| .RVML | Uncommon Files |
| .RVN | Uncommon Files |
| .RVO | Uncommon Files |
