R

File extensions starting with the letter R...

  .R    Pegasus Mail Resource File
        Progress Compiled Program File
  .R??  RAR Compressed File (?? can be 01 to 99)
  .R8   RAW Graphic File
  .R8L  LaserJet Landscape Font
  .R8P  LaserJet Portrait Font
  .RA   RealMedia File  [Viewer]
  .RAM  RealMedia Metafile
  .RAR  RAR Compressed Archive
  .RAS  Sun Raster Graphic  [Viewer]
        Cals Raster File [SwiftView]
  .RAT  Rating System File
  .RAW  RAW RGB 24-bit Graphic
        Raw Signed PCM Data
  .RAX  Image File
  .RB   RocketEdition File
  .RB1  R:Base Data File
  .RB2  R:Base Data File
  .RB3  R:Base Data File
  .RBF  R:Base Data File
  .RBH  RoboHelp Configuration
  .RC   Borland C++ Resource Compiler Script File
  .RCD  PC Anywhere Recorded Session File
  .RCP  Recomposer's MIDI Sequencer Music File
  .RD1  Descent1 Registered Level File
        DATAIR Retirement Document System Data File
  .RD2  DATAIR Retirement Document System Custom Text File
  .RD3  Ray Dream Designer Graphics
        CorelDream 3D
  .RD4  Ray Dream Designer Graphics
  .RD5  Ray Dream Designer Graphics
  .RDB  TrueVector Rules Database
  .RDF  Resource Description Framework File
        Chromeleon Report Definition
  .RDL  Descent Registered Level
        RadioDestiny Radio Stream
  .RDS  Ray Dream Studio File
  .RDX  Reflex Data File
  .REC  Sprint Record File
        Windows Recorder Macro
        RapidComm Voice File
  .REF  Cross Reference
  .REG  Registration Data
  .REM  Annotation (remark)
  .REP  Text Document
  .REQ  Request
  .RES  Resource File (various programs)
  .REX  REXX Program File
        Oracle Report Definition
  .REZ  Resources
  .RF   Sun Raster Graphic
        RealFlash Clip
  .RFD  RecogniFORM Form Definition
  .RFG  RFG Integrator System Database
  .RFH  RFG Integrator Householding Database
  .RFT  Revisable Format Text
  .RGB  Picture File
  .RGI  RealArcade Game Installer (not secured)
  .RGP  RealArcade Game Package
  .RGS  RealArcade Game Installer (secured)
  .RI   Lotus File
  .RIA  Alpharel Group IV Raster Graphics File
  .RIC  Ricoh Graphic File
  .RIF  Fractal Painter Bitmap
  .RIP  Remote Imaging Protocol
  .RIX  Colorix File
        RIX Virtual Screen
  .RL1  Descent1 Registered Level File
  .RL2  Descent2 Registered Level
  .RLA  Advanced Visualizer File
        Wavefront Raster Image
  .RLB  Harvard Graphic File (Harvard Graphics taken over by Serif)
  .RLC  Image Systems CAD Overlay
  .RLE  Graphic (Run Length Encoded)  [Viewer]
  .RM   RealMedia File
  .RMD  RegMaid Document
  .RMF  Rich Map Format (3D Games)
  .RMI  MIDI File  [Viewer]
  .RMK  RMake Make File
  .RMM  RealPlayer File
  .RMX  RealJukeBox MP3 File
  .RND  AutoCAD Rendering Slide
        AutoShade Format
  .RNG  Nokia Ringtone File
  .RNL  GTX Runlength Raster Graphics
  .RNX  RealPlayer File
  .ROL  Adlib Music
  .ROM  Nintento 64® Emulation ROM Image
  .ROV  Rescue Rover Data
  .RP   RealPix Clip
  .RPB  Automotive Diagnostic File
  .RPD  Rapidfile Database
  .RPM  RedHat Package Manager (Linux)
        RealMedia Player File
  .RPT  Report (various)
  .RQY  MS Excel OLE DB Query File
  .RR   Railroad Tycoon
  .RRS  Road Rash Save File
  .RSB  Rogue Spear Bitmap
  .RSF  Mediafour MacDrive Macintosh Resource Fork
  .RSL  PC Tools Resources Library
        Borland's Paradox 7 Report
        Adobe Pagemaker File
  .RSN  Propellerhead Reason Audio File
  .RSP  Responce Text File
        Rockwell Software Logix 5 File
  .RSS  Rockwell Logix 500 SLC-5 Software
  .RT   RealText Clip
  .RTA  RoboHelp Configuration
  .RTF  Rich Text Format
  .RTK  RoboHelp Configuration
  .RTL  Text File
  .RTM  Real Tracker Music Module
  .RTP  TurboTax Update File
  .RTS  RoboHelp Configuration
        RealAudio RTSL Document
  .RTX  Reliacast Audience Manager Turnstile
  .RUL  InstallShield
  .RUN  PC Tools Script Tools Program
  .RV   RealVideo Clip
  .RVP  Microsoft Scan Configuration File
  .RX   Reflex Database Driver
  .RXD  Reflex Database
  .RXH  Reflex Database Help File
  .RXR  Reflex Database Report
  .RXS  Reflex Database Screen Driver