.??_  Files ending in "_" are often compressed install files of the same
          name (e.g., .EX_ expands to .EXE, .DL_ expands to .DLL, etc.)
  .G    Applause Data Chart
        Cliq Accessories Datebook Schedule Group [Linux Suite PDF Description]
  .G3   G3 FAX File  [XnView] [IrfanView]
  .G32  GFA BASIC 32 Program File
        PaperPort File
  .G3D  GenDesigner 3.x Genealogy Database
  .G3F  Zetafax TIFF File (fine resolution)
  .G3N  Zetafax TIFF File (normal resolution)  [XnView]
  .G4   GTX RasterCAD File
        Access [XnView]
  .G42  ADAPTA DLS/32 Supply Chain Planning (ASCII file with info about SKUs and product-groups)
  .G53  ADAPTA DLS/32 Supply Chain Planning (ASCII file with info about Bills of Material)
  .G8   PicLab Plane Three Graphics
  .GAC  Global Audio Control Skin
  .GAF  Total Annihilation  [XnView]
  .GAL  Gallery of Pictures
        Corel Multimedia Manager Album
  .GAM  GammaFax Fax Document
        TADS 2.x Game File
        Baldur's Gate Game File
        Animated E-mail (unverified)
  .GAP  Electrical Generation Analysis and Planification
  .GAT  Gator File (password manager)
  .GAU  Gaussian Input File (MIME type chemical/x-gaussian-input)
        MS Flight Simulator Gauge  (e.g., altimiter.gau)
  .GAY  Reported as Sometimes a Porn File (presumably a renamed standard graphic file)
  .GB   Chinese
        Nintendo GameBoy Emulator ROM Image File
        Printfox/Pagefox  [XnView]
  .GBA  Nintendo® Game Boy Advance ROM Image
        GrabIt Batch Files
  .GBC  Nintendo® GameBoy Color Emulator ROM Image File
  .GBD  Gator Banner File
  .GBK  Interbase Database Backup
  .GBL  VAXTPU Global Definitions (VAXTPU is default OpenVMS editor)
  .GBR  GIMP Brush File  [GIMP]  [XnView]
        Gerber Format File (Graphics Language for the Electronics Industry) [Viewer]
  .GBS  Gameshark Online Save/Snapshot
  .GBT  Photoshop File
  .GC   Sierra Print Artist Greeting Card
  .GC1  Golden Common Lisp Source Code
  .GC3  Golden Common Lisp Source Code
  .GCA  GOCA Graphics File
        G Compression Archiver Compressed File (link is Japanese site) [Mime Type application/x-gca-compressed]
  .GCC  VISUAL EPR COSEUL.EXE Result (table of components of Cartesian tensors)
  .GCD  Generic CADD Drawing
        IsoBuster File
        Prassi CD Image
        GNUe Class Definition
  .GCF  WinXComp Grouped Compressed File
  .GCI  GTA2 Game File
        VISUAL EPR COSEUL.EXE Result (table of components of irreducible tensors)
  .GCM  GeoConcept Map File
        Group Mail CMessage Store File
  .GCP  Ground Control Point File (map projection)
  .GCR  VISUAL EPR COSEUL.EXE Output
  .GCT  ApplinX Screen Scrapper (unverified)
  .GDB  Interbase Database
        Group Mail File
  .GDF  GEOS Dictionary
  .GDM  Bells, Whistles, and Sound Boards Module
  .GDR  SymbianOS Bitmap Font File  (can contain multiple typefaces)
  .GDS  Image File
        Chip Layout Information
  .GED  GEDCOM Family History File
        EnerGraphics File
        Graphic Environment Document
        Arts & Letters Graphics File
  .GEM  GEM (a desktop interface) File
        Digital Research GEM Paint  [XnView]
        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
        GeoPaint  [XnView]
        Trumpf ToPs File (CAD/CAM, laser cutting)
  .GER  GerberView File (partial support for extended Gerber [RS-274X] file format)
  .GF   gFx UNIX Plotting Program
        METAFONT Generic Font File
        Geometric Data
        Pilot Logbook for Grok File
        Starfleet Command - Empires At War File
  .GFA  Bitmap Graphics File (see .GFX/Warcraft; files are similar)
  .GFB  GIFBlast Compressed GIF Image
  .GFC  Patton & Patton Flowcharting 4 File
  .GFD  Menus for GNUe Forms
        VISUAL EPR Energy, Fields File
  .GFI  Genigraphics Graphics Link Presentation
  .GFT  NeoPaint Font
  .GFX  Genigraphics Graphics Link Presentation
        WarCraft II Image File
  .GFY  Grafical 1.0 File
  .GG   Sigmac Compiled Machine Code
        Gridgen File
        Sega GameGear Game ROM Image
        Koala Paint Compressed File  [XnView]
  .GG1  Goofy Golf Deluxe Course
  .GG2  Goofy Golf Deluxe Saved Game
  .GGI  GGI Extension
  .GGP  GemCom Graphic Format
  .GHO  Symantec Ghost Disk Image File
  .GHS  Lasertank High Scores
  .GI   Sony CD Extreme Global Image File
  .GIB  Graph-in-the-Box Chart
  .GID  Windows Help Index File
  .GIF  Graphic Interchange Format  [XnView] [IrfanView]
  .GIFF  Graphic Interchange Format  [XnView] [IrfanView]
  .GIG  Sound File
  .GIM  Genigraphics Graphics Link Presentation
  .GIW  Graph-in-the-Box Presentation
  .GIX  Genigraphics Graphics Link Presentation
  .GJD  7th Guest Game Archive
        11th Hour Game Archive  [Dragon UnPACKer]
        GetJet Professional Database (really an Access database)
  .GJF  Gaussian Input Data File
  .GKH  Ensoniq EPS Family Disk Image
  .GKS  Gravis GripKey Document
  .GL   GRASP - Graphical System for Presentation File
  .GLD  Glide File
  .GLM  Glim Data File
  .GLY  MS Word Glossary [Buy Office XP at Shop.Microsoft]
  .GM   Autologic  [XnView]
  .GM2  Autologic  [XnView]
  .GM4  Autologic  [XnView]
  .GM?  Heroes of Might & Magic III Saved Game (? = number of human players in game)
  .GMAX  gmax Game Creator
  .GMD  Game Maker Stored Game (game under development--also see .GMR)
  .GME  Interact DexDrive Playstation Memory Card Save
  .GMF  Applause CGM Graphics
  .GMM  Group Mail Message Log File
  .GMP  GTA2 Game File
        Group Mail List Information File
        Geomorph Tile Map
  .GMR  Schlafhorst Automation Graphical Monitor Record
        Game Maker Compiled Game (finished game--also see .GMD)
  .GMS  Corel Global Macro File
  .GMT  Scarlett Expert System Compiler Grammar File (Scarlett is not presently available)
  .GMX  Group Mail Message File
  .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  [Dragon UnPACKer]
        Indiana Jones 3D Archive  [Dragon UnPACKer]
  .GOC  Geoworks Goc Source Code
  .GOH  Geoworks Goc Header
  .GOO  Kai's Power Goo / Kai's Supergoo
  .GOR  Gorilla (Film & Video Production Management)
  .GP   Geoworks Glue Geode Parameter File
  .GP3  CCITT Group 3 File (fax)
        GuitarPro 3
  .GP4  CCITT Group 4 File (fax)
  .GPD  VISUAL EPR Input Data for PARAMS.EXE
  .GPF  Believed to be a Japanese graphic file
  .GPG  GnuPG Encrypted File (usually compatible with .PGP files)
  .GPH  Lotus 1-2-3 Graph
        Stata Graph
  .GPK  Omnigo Program Package  [Added Info]
  .GPL  GPS Log File (used by mapping software)
  .GPP  GraphPap Graph Paper File
        Serif GraphicsPlus Object
  .GPR  VISUAL EPR PARAMS.EXE Results
  .GPS  Pocket CoPilot GPS Tracks Data File
  .GPX  BASIS File
  .GQA  BI/Query Data Model Admin Layer
  .GQL  BI/Query Data Model (used to be Andyne GQL)
  .GQU  BI/Query Data Model User Layer
  .GR   XGMML (eXtensible Graph Markup and Modeling Language) File
  .GR2  Windows 3.0 Screen Driver
  .GR3  Windows 3.0 Screen Grabber
  .GRA  Flight Simulator File
        MS Graph Chart
        SigmaPlot Data File
        STN Express Transcript Graphics File  (search science databases through STN®)
  .GRAAL  Offical Graal Level
  .GRB  MS-DOS Shell Monitor
  .GRD  Gradebook Power File
        Map Projection Grid File
  .GREY  Picture File (raw GREY graphics) RAW RGB 24-bit Graphic  [XnView]
  .GRF  Graph
        Graph Plus Graph File
        Golden Software Graph File
        Grafix Idea File
        Graph Edit File [Part of DirectX SDK]
        DLG "Graphic" Format
  .GRL  Matlab Graphic Format
  .GRM  VISUAL EPR Input Data for FIntGraf
  .GRN  Granny 3D Rendering Program
  .GRO  Serious Sam Game File  [Dragon UnPACKer]
        Warlords Battlecry Archive  [Dragon UnPACKer]
        HP-48/49 GROB  [XnView]
  .GRB  HP-48/49 GROB  [XnView]
  .GRP  Windows Program Manager Group
        PixBase Pictures Group
        Duke Nukem 3D Archive  [Dragon UnPACKer]
        Shadow Warrior Archive  [Dragon UnPACKer]
  .GRQ  Quickstep Barco Graphics
  .GRS  Packedge Barco Graphics
  .GRT  VISUAL EPR Calculation Results of Fields
  .GRV  Groove Networks File
  .GRX  GetRight File List
  .GRY  Picture File (raw GREY graphics) RAW RGB 24-bit Graphic  [XnView]
  .GS1  GraphShow Presentation
  .GSC  GeneStudio File (Molecular Biology Software)
  .GSD  Professional Draw Vector Graphics
  .GSM  Raw GSM 6.10 Audio Stream (Global System for Mobile Audio)
        Sound File [Linux Player]
        US Robotics Modem File
  .GSP  Geometer's Sketchpad Material File
  .GSW  GraphShow Worksheet
  .GT2  Graoumftracker Music Module (new)
  .GTK  Graoumftracker Music Module (old)
  .GTP  GuitarPro File
        MultiFS Video File
  .GTS  Genome Software Tempo Alarm Clock
  .GTY  Gibson Tray File
  .GUP  PopMail Data
  .GUR  Gutsch & Exner Software Update Undo
  .GUX  Gutsch & Exner Software Update
  .GV   Grandview (DOS-based outline program by John Friend who licensed to Living Videotext; bought by Symantec)
  .GWI  Groupwise File (binary file that contains link information)
  .GWP  Greetings WorkShop File  [Now MS Picture It!]
  .GWS  GeoMedia Geoworkspace File
  .GWX  Genigraphics Graphics Link Presentation
  .GWZ  Genigraphics Graphics Link Presentation
  .GX1  Show Partner Graphics File
  .GX2  Show Partner Graphics File
  .GXC  General CADD Pro File
  .GXD  General CADD Pro File
        GX-Reports File
        Jeol EX Spectrometer Data File
  .GXF  General CADD Pro File
  .GXL  Genus Graphics Library
  .GXM  General CADD Pro File
  .GXP  Jeol EX Spectrometer Data File
  .GXR  Genexus Report Viewer
        GX-Reports File
  .GXT  GTA2 Game File
  .GYM  Sega Genesis Music Logged Format
  .GZ   Gzip Compressed Archive
  .GZIP  Gzip Compressed Archive (more usually seen as .GZ)