| 1 | G | Corel | Corel Paradox Format |
| 2 | G3 | CCITT | CCITT Group 3 Fax Image |
| 3 | G3N | Equisys | Imaging Fax Image |
| 4 | GADGET | Microsoft | Windows Gadget |
| 5 | GAF | Cavedog Entertainment | Total Annihilation Animated Bitmap Format |
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| 6 | GAI | Adobe Systems Incorporated | Adobe SING Glyphlet Manager |
| 7 | GAM | N/A | Saved Game Format |
| 8 | GAX | Microsoft Studios | Age Of Empires II Save Game |
| 9 | GB | N/A | Game Boy ROM Format |
| 10 | GBA | N/A | Game Boy Advance ROM |
| 11 | GBC | N/A | Game Boy Color ROM |
| 12 | GBI | gBurner Systems | GBurner Project Format |
| 13 | GBLORB | N/A | Interactive Fiction |
| 14 | GBM | Genie-Soft Corporation | Genie Backup Manager Archive |
| 15 | GBP | Genie-Soft | Gerber Bottom Paste Mask Output Format |
| 16 | GBPROJ | Apple | GarageBand Project |
| 17 | GBR | GIMP | GIMP Brush Image Format |
| 18 | GBS | N/A | GameBoy Sound Format |
| 19 | GCA | N/A | GCA Format Archive |
| 20 | GCD | General CADD Products | Prassi CD Disk Image Format |
| 21 | GCF | Valve | Game Cache Format |
| 22 | GCH | The GNU Project | C++ Precompiled Header |
| 23 | GCM | Nintendo | GameCube ROM |
| 24 | GCODE | N/A | G-code Source |
| 25 | GCX | Apple | Grapher Graph Format |
| 26 | GDB | Borland | InterBase Database Format |
| 27 | GDOC | Google | Google Drive Document |
| 28 | GDOCX | Google | Google Drive Document |
| 29 | GDRAW | Google | Google Drive Drawing |
| 30 | GED | The LDS Church | GEDCOM Genealogy Data Format |
| 31 | GEL | N/A | Molecular Dynamics Image |
| 32 | GEM | Deltasoft | GEM Vector Picture Format |
| 33 | GEMFILE | Ruby community | Ruby RubyGems |
| 34 | GEMSPEC | RubyGems | Gem Specification Format |
| 35 | GEO | N/A | VRML Geography Format |
| 36 | GEOJSON | GeoJSON | GeoJSON Format |
| 37 | GER | N/A | German Text/html Info |
| 38 | GERBER | N/A | Printed circuit board photoplotter data |
| 39 | GFF | Roche NimbleGen, Inc. | SignalMap Gene-Finding Format (GFF) Data |
| 40 | GFORM | Google | Google Drive Form |
| 41 | GFS | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove Remote |
| 42 | GG | Google | Google Desktop Gadget Format |
| 43 | GHC | Microsoft Corporation | Visual Basic Constant Map |
| 44 | GI | N/A | Global Image |
| 45 | GI! | N/A | GigaSampler/GigaStudio Split |
| 46 | GIF | CompuServe | Graphical Interchange Format |
| 47 | GIFF | N/A | CompuServe Bitmap Image(Graphics Interchange Format) |
| 48 | GIFT | N/A | Generic |
| 49 | GIF_160X120 | N/A | GIF image |
| 50 | GIF~C200 | N/A | Graphics Interchange Format file |
| 51 | GIG | Tascam | Tascam GigaSampler Format |
| 52 | GIM | Sony | PlayStation Portable Image Format |
| 53 | GITATTRIBUTES | Scott Chacon | Pro Git Attribute |
| 54 | GITIGNORE | Git | Git Ignore Format |
| 55 | GJD | Trilobyte | The 7th Guest Media Format |
| 56 | GLADE | The Glade Project | Glade Project Format |
| 57 | GLK | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove Shortcut |
| 58 | GLOS | Microsoft Corporation | Microsoft Word For Mac Glossary |
| 59 | GLOX | Microsoft | Microsoft Office SmartArt Graphics Layout Format |
| 60 | GLTF | The Khronos Group | GL Transmission Format File |
| 61 | GLY | Microsoft | Word Glossary Format |
| 62 | GM | GameMonkey Script | GameMonkey Script |
| 63 | GMANIFEST | Google Inc. | Google Desktop Gadget Control |
| 64 | GMI | Megalith-Systems | GPS Tuner Map Calibration Data |
| 65 | GML | Galdos Systems | Geography Markup Language Format |
| 66 | GMW | Global Mapper Software LLC | Global Mapper Workspace |
| 67 | GNC | N/A | Great Notions Embroidery |
| 68 | GNE | Ludicorp | Flickr Web Page |
| 69 | GNU | N/A | Generic |
| 70 | GNUMAKEFILE | GNU | GNU Makefile |
| 71 | GO | Google | Google Go Programming Language Source Code |
| 72 | GOB | LucasArts Entertainment Company, LLC | LucasArts Game Resource |
| 73 | GOLD | The GNOME Project | Gnome Desktop |
| 74 | GP | Arobas Music | Guitar Pro |
| 75 | GP3 | Arobas Music | Guitar Pro 3 Format |
| 76 | GP4 | Arobas Music | Guitar Pro 4 Tablature |
| 77 | GP5 | Arobas Music | Guitar Pro 5 Tablature Format |
| 78 | GPB | N/A | Gerber Bottom Pad Master |
| 79 | GPD | Microsoft | Generic Printer Description Format |
| 80 | GPL | GIMP | GNU Public Licence Text |
| 81 | GPW | Autodesk, Inc. | Autodesk AutoCAD Civil 3D Hydraflow Hydrographs Extension |
| 82 | GPX | N/A | GPS Exchange Format |
| 83 | GRAPHML | The GraphML Team | GraphML Format |
| 84 | GRD | Adobe Systems | Photoshop Gradient Format |
| 85 | GREY | N/A | Raw Image Format |
| 86 | GRO | Hewlett-Packard | Graphic Object Bitmap |
| 87 | GROOVY | VMware, Inc. | Groovy Source Code Format |
| 88 | GROUPPROJ | Embarcadero Technologies | Delphi Project Group Format |
| 89 | GRS | Headlight Software, Inc. | GetRight Skin |
| 90 | GRV | Microsoft | Office Groove Format |
| 91 | GRXML | N/A | Grammar |
| 92 | GSA | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove Working Space Archive Or Template |
| 93 | GSB | Golden Software | Golden Software Boundary Format |
| 94 | GSHADER | N/A | Microsoft Visual Studio data |
| 95 | GSHEET | Google | Google Drive Spreadsheet |
| 96 | GSI | Golden Software | Golden Software Interchange Format |
| 97 | GSL | Siber Systems, Inc. | GoodSync Job List |
| 98 | GSLIDES | Google | Google Drive Presentation |
| 99 | GSR | Golden Software | Golden Software Reference Format |
| 100 | GSX | N/A | Sega Genesis Emulator Saved State Format |
| 101 | GT | N/A | Gold Thread Embroidery Format |
| 102 | GTA | Microsoft | Microsoft Groove Tool Archive |
| 103 | GTABLE | Google | Google Drive Fusion Table |
| 104 | GTAR | Free Software Foundation | GNU Tar Archive |
| 105 | GTI | Georgia Tech Research Corporation | STRUDL Input |
| 106 | GTO | Intuit Inc. | Quicken Online Data |
| 107 | GTP | Arobas Music | Guitar Pro Format |
| 108 | GTS | CaptiveWorks | CaptiveWorks PVR Video Format |
| 109 | GVG | Kompass | Kompass Map |
| 110 | GVY | VMware, Inc. | Groovy Source Code Format |
| 111 | GXF | General CADD Products | General CADD Pro Font Format |
| 112 | GXL | R. C. Holt | Graph Exchange Language Format |
| 113 | GYP | Microsoft Corporation | Google Chromium GYP Input Configuration |
| 114 | GYPI | N/A | Chrome/Chromium Include |
| 115 | GZ | The GNU Project | Gnu Zipped Archive |
| 116 | GZA | N/A | IZArc BGA Archive Format |
| 117 | GZI | N/A | Unix Gzip Format |
| 118 | GZIP | N/A | Gnu Zipped Format |
