| fts | Windows Help Full-Text Search Index |
| ftw | Family Tree Maker Document |
| ftxt | Cloanto C1-Text Document |
| fvml | FormVista Document |
| fw3 | Framework III File |
| fwk | Colton Fireworkz Document |
| fwrt | FullWrite Document |
| fwtb | Freeway Template Bundle |
| fwtemplate | Freeway Template |
| fwtemplateb | Freeway Template Bundle |
| fx2 | Corel WordPerfect Office Template |
| fxd | FX Draw Document |
| fxd | WinFax Document |
| fxi | WinFax Document |
| fxm | WinFax Document |
| fxo | WinFax Document |
| fxp | FontExpert Document |
| fxr | WinFax Document |
| fxs | WinFax Document |
| fxy | Fortron Embroidery Format Document |
| fzs | FuzzySheet Document |
| g | BRL-CAD Geometry Document |
| gabw | AbiWord Gzip Compressed Document |
| gb0 | Gerber Format Document |
| gb1 | Gerber Format Document |
| gbr | Gerber Format Document |
| gbxml | gbXML Document |
| gcd | General Content Descriptor |
| gcx | Macintosh Grapher Document |
| gdb | SmartWare Business Graph Definition File |
| gdc | Iconics GraphWorx32 Display for WinCE |
| gdc | SmartWare Composite Graph Definition File |
| gde | SmartWare Elevation Graph Definition File |
| gde | The Guide Document |
| gdf | Iconics GraphWorx32 Display |