| fru | FreeIPMI FRU Data |
| frv | Microsoft FRx DrillDown Viewer File |
| frz | Microsoft FRx DrillDown Viewer Compressed File |
| fs | RMCProfile Sulphur and Fluorine Data |
| fsa | ABI Fragment Analysis Data |
| fsac | File Search Assistant Data |
| fsat | Autodesk Inventor Stress Analysis FSAT Data |
| fsd | FacetWin File Set Description |
| fsdb | Novas Software Waveform File |
| fse | Epson Projector Scenario Data |
| fset | Fact200 Results Data |
| fseventsd | Mac OS X FSEvents Data |
| fsf | FSL Feat Setup Script |
| fsif | MyLabel Designer Deluxe Data |
| fsk | Atari 8-bit Tape Data |
| fsm | Splitty Master Split Data |
| fso | Adobe Flash Media Server Remote Shared Object |
| fsp | iGO Primo Map File |
| fsqueue | FeedStation Queue Data |
| fsrc | Fact200 Source Code |
| fss | Splitty Data Split |
| fssx | FolderSizes Snapshot Data |
| fst | FAST Input Data |
| fst | GAUSS Engine String Data |
| fst | PLINK Fixation Index Report |
| fstat | SAM Fragfinder Scoring Data |
| fsthumb | Wondershare Filmora Thumbnail Cache |
| fstrm | Frame Streams Protocol Data |
| fsz | Fractal Zplot Data |
| ft | EdgeCAM Feature Template |
