| gmb | WinDS PRO Data |
| gmbck | Game Maker Background Image |
| gmbl | Vernier Logger Lite Data |
| gmc | CircuitCAM GMC Library |
| gmc | Global Mapper Catalog Data |
| gmd | Great Budget Model Data |
| gmd | GroupMail Message Data |
| gmd | Nintendo 3DS Game Dialog Data |
| gme | DexDrive Game Card Image |
| gme | Multi Game Memory Editor Main Game Data |
| gmf | GameExchange2 Material Data |
| gmf | GenStat Data |
| gmf | Leadwerks 3D Model |
| gmf | SmartWare Pre 1.5 Graph Metafile |
| gml | Girder Plugin |
| gml | Graphlet GraphScript Data |
| gmmod | Game Maker 3D Model |
| gmp | Geomorph Tilemap Data |
| gmp | GroupMail Data |
| gmr | Schlafhorst Graphical Monitor Record |
| gmres | Game Maker Resource |
| gms | GAMS Model File |
| gms | Gesture and Motion Signal Format Data |
| gmspr | Game Maker Sprite |
| gmt | GenePattern Gene Matrix Transposed File |
| gmv | General Mesh Viewer Input Data |
| gmx | GenePattern Gene Matrix File |
| gmx | GroupMail Data |
| gmx | GroupMail Database |
| gmx | GroupMail Message Data |
| gmxml | Mercury Generated Motif Data |
| gmy | HemeLB Geometry Data |
| gna | Genigraphics Graphics Link Presentation |
| gnc | GnuCash Financial Data |
| gnc | Great Notions Embroidery Data |
