| grxml | XML Grammar File |
| gs | GemStone Document |
| gs-bck | Genius Scan Backup Data |
| gs1 | Genecyst Emulator Saved State |
| gs2 | Genecyst Emulator Saved State |
| gs3 | GameStarter File |
| gs3 | Genecyst Emulator Saved State |
| gs4 | Genecyst Emulator Saved State |
| gs5 | Genecyst Emulator Saved State |
| gs6 | Genecyst Emulator Saved State |
| gs7 | Genecyst Emulator Saved State |
| gs8 | Genecyst Emulator Saved State |
| gs9 | Genecyst Emulator Saved State |
| gse | GeneSys 3 Export File |
| gsf | z-Tree GameSafe Data |
| gsf | MODFLOW Grid Specification Data |
| gsf | GameExchange2 Skeleton Data |
| gsf | GEMPAK Map File |
| gsf | Gwyddion Simple Field File |
| gsk | GSAK Macro File |
| gslib | Geostatistical Software Library Data |
| gsp | Tascam Gigastudio Performance Data |
| gss | Geometer Sketchpad Script |
| gsv | Gameshark SP Save File |
| gsx | Genecyst Emulator Saved State |
| gsym | Rocket D3 Global Symbol Data |
| gt6 | Topcon Link GTS-6 Raw Data |
| gt7 | Topcon Link GTS-7 Raw Data |
| gtable | Google Drive Fusion Table |
| gtar | GNU Tar Archive |
| gtb | Midas GTS Data File |
| gtd | GT Designer 2 Data |
| gte | GigaTrust Client Protected Data |
| gtf | Gene Transfer Format File |
| gtfs | General Transit Feed Specification Data |