| gus | XMVB Orbital Guess Data |
| gvar | PLINK Genetic Variant File |
| gvd | Gladinet Cloud Data |
| gvf | Genome Variation Format Data |
| gvfx | Microvellum Global File |
| gvs | GuitarVision Data |
| gw | SWAT Groundwater Input Data |
| gwa | AMAPstudio Geometry with Attributes Data |
| gwc | Groundspeak Compiled Wherigo Cartridge |
| gwg | OxMetrics Graphics Data |
| gwl | Groundspeak Wherigo Cartridge Log |
| gws | Groundspeak Wherigo Save File |
| gwt | GeoDa Distance Weights Data |
| gwv | Groundwater Vistas Packaged Model |
| gwy | Gwyddion Surface Data |
| gwz | Groundspeak Wherigo Cartridge Archive |
| gx | GenX Data |
| gx2 | General CADD Pro Image |
| gxa | General CADD Attribute Data |
| gxc | General CADD Pro Component |
| gxh | General CADD Pro Hatch |
| gxl | Graph Exchange Language |
| gxm | General CADD Pro Macro |
| gxs | GrafiXML Graph |
| gxv | General CADD Pro Menu |
| gxy | ISIS GIS Visualiser Schematic Data |
| gyg | Gygan Data |
| gz1 | Orgadata LogiKal Data |
| gzf | WebCopier Data |
| gzl | Go!Zilla File List |
| h00 | Flash ROM HEX File |
| h01 | Flash ROM HEX File |
| h02 | Flash ROM HEX File |
| h03 | Flash ROM HEX File |
| h1c | Microsoft Help Collection Definition |