File extensions starting with the letter G...

  .G3   G3 FAX File  [Viewer]
  .G32  GFA BASIC 32 Program File
  .G3F  Zetafax TIFF File (fine resolution)
  .G3N  Zetafax TIFF File (normal resolution)
  .G4   GTX RasterCAD File
  .GAL  Gallery of Pictures
        Corel Multimedia Manager Album
  .GAM  GammaFax Fax Document
  .GAT  Gator File
  .GB   Chinese
        Nintendo GameBoy Emulator ROM Image File
  .GBA  Nintendo® Game Boy Advance ROM Image
        GrabIt Batch Files
  .GBC  Nintendo® GameBoy Color Emulator ROM Image File
  .GBK  Interbase Database Backup
  .GBL  VAXTPU Global Definitions (VAXTPU is default OpenVMS editor)
  .GC   Sierra Print Artist File
  .GC1  Golden Common Lisp Source Code
  .GC3  Golden Common Lisp Source Code
  .GCA  GOCA Graphics File
  .GCD  Generic CADD Drawing
        IsoBuster File
  .GCF  WinXComp Grouped Compressed File
  .GCI  GTA2 Game File
  .GCP  Ground Control Point File (map projection)
  .GDB  Interbase Database
  .GDM  Bells, Whistles, and Sound Boards Module
  .GDS  Image File
  .GED  GEDCOM Family History File
        Graphic Environment Document
        Arts & Letters Graphics File
  .GEM  GEM (a desktop interface) File
        Ventura Publisher Vector Graphics
  .GEN  Ventura-Generated Text File
        Chromeleon Generic Driver Configuration
        dBase Application Generator Compiled Template
  .GEO  VideoScope File
        GeoSoft Compressed Add-on
        Geoworks Geode
  .GFA  Bitmap Graphics File
  .GFC  Patton & Patton Flowcharting 4 File
  .GFI  Genigraphics Graphics Link Presentation
  .GFT  NeoPaint Font
  .GFX  Genigraphics Graphics Link Presentation
  .GHO  Symantec Ghost Disk Image File
  .GID  Windows Help Index File
  .GIF  Graphic Interchange Format  [Viewer]
  .GIM  Genigraphics Graphics Link Presentation
  .GIX  Genigraphics Graphics Link Presentation
  .GKH  Ensoniq EPS Family Disk Image
  .GKS  Gravis GripKey Document
  .GL   GRASP - Graphical System for Presentation File
  .GLY  MS Word Glossary
  .GMP  GTA2 Game File
  .GMR  Schlafhorst Automation Graphical Monitor Record
  .GNA  Genigraphics Graphics Link Presentation
  .GNO  Genopro Genealogy Document File
  .GNT  Micro Focus Generated Code
  .GNX  Genigraphics Graphics Link Presentation
  .GOB  Dark Forces Game File
  .GOC  Geoworks Goc Source Code
  .GOH  Geoworks Goc Header
  .GP   Geoworks Glue Geode Parameter File
  .GP3  CCITT Group 3 File (fax)
  .GP4  CCITT Group 4 File (fax)
  .GPF  Believed to be a Japanese graphic file
  .GPH  Lotus 1-2-3 Graph
  .GPK  Omnigo Program Package  [Added Info]
  .GPP  GraphPap Graph Paper File
        Serif GraphicsPlus Object
  .GR2  Windows 3.0 Screen Driver
  .GR3  Windows 3.0 Screen Grabber
  .GRA  Flight Simulator File
        MS Graph Chart
        SigmaPlot Data File
  .GRB  MS-DOS Shell Monitor
  .GRD  Gradebook Power File
        Map Projection Grid File
  .GRF  Graph
        Golden Software Graph File
        Grafix Idea File
  .GRN  Granny 3D Rendering Program
  .GRP  Program Manager Group
  .GRV  Groove Networks File
  .GRX  GetRight File List
  .GRY  Picture File
  .GSM  Raw GSM 6.10 Audio Stream
        US Robotics Modem File
  .GSP  Geometer's Sketchpad Material File
  .GT2  Graoumftracker Music Module (new)
  .GTK  Graoumftracker Music Module (old)
  .GTY  Gibson Tray File
  .GUP  PopMail Data
  .GWP  Greetings WorkShop File  [Now MS Picture It!]
  .GWX  Genigraphics Graphics Link Presentation
  .GWZ  Genigraphics Graphics Link Presentation
  .GX1  Show Partner Graphics File
  .GX2  Show Partner Graphics File
  .GXL  Genus Graphics Library
  .GXT  GTA2 Game File
  .GZ   Gzip Compressed Archive