| ffs_db | FreeFileSync Database |
| fft | Farm Foresty Toolbox Data |
| ffteeth | FaceFilter Teeth Data |
| ffv | Fisher FirstVue Data |
| ffx | Microsoft Find Fast Index |
| ffxptheme | FlashFXP Toolbar Theme Data |
| fga | Folder Guard Attributes File |
| fgb | Talysurf CCI 3000 Frame Sequence Data |
| fgd | Folder Guard Data File |
| fgdb | Fontographer Mac Database |
| fgf | Nav.Net NG Fusker Generator Data |
| fgp | Folder Guard Password File |
| fgr | FRSGiftRegistry Data File |
| fgt | FreeGantt Skeleton Data |
| fgv | CellexalVR FGV Data |
| fh50 | Adobe FreeHand Creator Code |
| fhb | ForeHelp Backup File |
| fhc | Canute FHC Data FIle |
| fhd | MODFLOW Model Head Data |
| fhf | Free Hide Folder Backup |
| fhi | ABINIT FHI Data |
| fhq | Family Historian Query |
| fhr | Family Historian Data |
| fht | Family Historian Text Scheme Data |
| fhx | DeltaV Database File |
| fh_proj | Family Historian Project |
| fia | FIA Input Data |
| fib | File Investigator Internal Database |
| fid | File Investigator Internal Database |
| fidx | Fiasco Database Index Data |
| fiff | Elekta Neuromag FIFF Data |
| fig | SNES ROM Image FIG |
| fih | File Investigator Internal Database |
| fik | MATLAB File Installation Key |
| fil | ACL for Windows Data |