| g3m | Casio Prizm Main Memory Data |
| g4 | Gerber Inner Routing Layer 1 Data |
| g64 | Genetec Omnicast Video Archive |
| g8 | Cubicomp PictureMaker Green Channel Image Data |
| g99 | HEC-RAS Geometry File |
| ga | STK Great Arc Propagator File |
| ga3 | Graphical Analysis 3 Document |
| gaa | GAL-ANA Data File |
| gad | Intergado Data File |
| gad | GeoDict Analytic Data |
| gadgeprj | Gadge It Project |
| gaf | GameExchange2 Animation |
| gai | Adobe Glyphlet Development Kit Glyphlet |
| gal | GenePix Array List |
| gal | Corel Multimedia Manager v6 Album |
| gallery | SMART Notebook Gallery |
| gallerycollection | SMART Notebook Gallery Collection |
| galleryitem | SMART Notebook Gallery Item |
| gam | General Game Data File |
| gam | Gamma Card Data |
| gam | Aureas Theme File |
| gaml | GAML Document |
| gap | Generation Analysis and Planning Data |
| gas | Grab-a-Site Data File |
| gasx | GOM Player Data |
| gat | GATTer Configuration Data |
| gb | Nintendo GameBoy ROM Image |
| gb3 | Geekbench 3 Report |
| gba | Nintendo GameBoy Advance ROM Image |
| gba | GrabIt Batch |
