| fred | Flight Recorder Electronic Documentation Data |
| freq | SAM Frequency Model Data |
| fres | Autodesk Inventor Stress Analysis Results Data |
| frf | Abbyy FineReader Intenal Page Data |
| fri | Fractal Explorer IFS Spot |
| frk | FORMIK Data |
| frm | EZ-Forms Master Form |
| fro | Fractal Explorer Orbita Spot |
| fro | dBASE IV Compiled Report |
| frp | Fractal Explorer Palette |
| frq | Lucene Frequencies File |
| frq | PLINK Basic Allele Frequency Report |
| frqx | PLINK Genotype Count Report |
| frs | Fractal Explorer Spot |
| fru | FreeIPMI FRU Data |
| frv | Microsoft FRx DrillDown Viewer File |
| frz | Microsoft FRx DrillDown Viewer Compressed File |
| fsa | ABI Fragment Analysis 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 |
| fss | Splitty Data Split |
| fst | GAUSS Engine String Data |
| fst | PLINK Fixation Index Report |
| fst | FAST Input Data |