| fcpxdest | Final Cut Pro Share Destination Data |
| fcs | Canon ZoomBrowser EX Data |
| fcs | Flow Cytometry Standard Data |
| fcs | Rapidform Polygon Faces Data |
| fcst | Delft-FEWS Forecast Data |
| fct | FolderClone Task List |
| fcxr | FileCapsule Deluxe Data |
| fcxu | FileCapsule Deluxe Data |
| fcz | Poser Compressed Face Data |
| fd | STK Facility Database Main File |
| fd1 | Windows Live Photo Gallery Thumbnail Database |
| fdat | Fiasco Database Data File |
| fdata | NONMEM Data |
| fdb | Firebird SQL Database |
| fdb | FormTool Pro Form Data |
| fdc | Autodesk AutoCAD Fields Description |
| fdd | FlexiDATA Database |
| fde | AFP Form Definition |
| fde | FLAMES Dataset Export Data |
| fdf | Format Description File |
| fdf | Origin Fitting Function Definition 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 | Epson PhotoQuicker Frame |
| fdp | Viamichelin Map File |
| 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 |
