| grr | Gradekeeper Class Roster |
| grs | Getright Skin |
| grt | Grapher Template |
| gru | FXpansion GURU Preset |
| grv | CART Grove Data |
| grv | Microsoft Office Groove File |
| grx | Getright Exported List |
| grxml | XML Grammar File |
| gs | GemStone Document |
| 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 | Gwyddion Simple Field File |
| gsf | GameExchange2 Skeleton Data |
| gsf | GEMPAK Map File |
| gsk | GSAK Macro File |
| gsr2 | Golden Software Reference |
| gss | Geometer Sketchpad Script |
| gsv | Gameshark SP Save File |
| gsx | Genecyst Emulator Saved State |
| gt6 | Topcon Link GTS-6 Raw Data |
