| fdat | Fiasco Database Data File |
| fdata | NONMEM Data |
| fdb | Firebird SQL Database |
| fdc | Autodesk AutoCAD Fields Description |
| fdd | FlexiDATA Database |
| fde | AFP Form Definition |
| fdf | Origin Fitting Function Definition File |
| fdf | Format Description File |
| fdff | Fast Duplicate File Finder Data |
| fdk | Fluentizer Dictionary Data |
| fdlang2 | FeedDemon Language Data |
| fdlang4 | FeedDemon Language Data |
| fdm | SIPINA FDM Data |
| fdn | MODFLOW Drawdown Data |
| fdo | ModelSim Script |
| fdp | Viamichelin Map File |
| fdp | Epson PhotoQuicker Frame |
| fdpart | Fresh Download Partial Downloaded File |
| fdrp | Mac OS X Folder Alias Data |
| fdsrch2 | FeedDemon Search Data |
| fdt | Lucene Field Data |
| fdt | Visilogic Utilities Full Data Table |
| fdx | Lucene Field Index |
| fdx | Food Data Exchange File |
| fdxsl2 | FeedDemon Newspaper Style |
| fdxsl4 | FeedDemon Newspaper Style |
| fe | Surface Evolver Data File |
| feap | Enterprise Architect Repository |
| feat | Feature Chemical Modeller Output Data |
| feb | Sybase PowerDesigner Free Model Backup |
