| fstrm | Frame Streams Protocol Data |
| fsz | Fractal Zplot Data |
| ft | EdgeCAM Feature Template |
| fta | OpenFTA File |
| ftbl | PIPE-FLO Fluid Data Table |
| ftch | Extensis Portfolio Image Database |
| ftes | Autodesk Inventor Stress Analysis Test Data |
| ftf | Xperia X10 Phone FTF Firmware |
| fth | FileMaker Pro Theme |
| ftmb | Family Tree Maker Backup Data |
| ftploc | Mac OS X Finder FTP Location Data |
| ftpquota | Pure-FTPd Quota Data |
| ftr | CONDOR Flight Track |
| ftv | CleverPath Forest and Trees View File |
| ftw | FontTwister Saved Text Effect |
| fuc | Frequently Used Commands |
| fud | FairUse Wizard Data File |
| ful | Microsoft Backup File List |
| furl | Fact200 Main Index Data |
| fus | FXpansion Uninstall Script |
| futr | NetIQ Identity Manager Future-dated Infotype Cache |
| fv | Fresh View Thumbnail Cache |
| fvb | TAC Vista Database Backup |
| fvd | DatABEL Filevector Data |
| fve | BitLocker Full Volume Encryption File |
| fvf | FlukeView File |
| fvi | DatABEL Filevector Index |
| fvl | Sanscript Library Cabinet File |
| fvp | ANSYS Fluent Path Line Data |
| fvr | NoteTab Favorites File |
| fvs | Forest Vegetation Simulator Tree Data |
| fvu | File Validation Utility Report |
| fw2 | Framework II File |
| fwaction | Freeway Action |
| fwactionb | Freeway Action Bundle |