| forth | Forth Source Code |
| fox | FoxBase Compiled Executable |
| fpa | Front Panel Express Order Data |
| fpd | Front Panel Express Design |
| fpgt | Flowgorithm Program Template |
| fpp | Fortran Source Code |
| fpq | Microsoft Visual FoxPro Updatable Query File |
| fprg | Flowgorithm Program |
| fps | FPS Creator Segment |
| fpt | Visual FoxPro Memo |
| fr3 | FastReport v3 Form |
| frf | FreeReport Form |
| frg | DBase IV Uncompiled Report |
| frm | Visual Basic Form |
| frt | Forth Source Code |
| frt | Visual FoxPro Report Memo |
| frx | Visual FoxPro Report |
| fs | F# Implementation |
| fs | Forth Source Code |
| fsb | Form Z Compiled Script |
| fscr | ChromeEd Forester Data Script |
| fsi | F# Signature File |
| fsl | Form Z Script |
| fsq | CryENGINE Facial Editor Sequence |
| fsscript | F# Script |
| fsx | F# Script |
| ftd | Falcon Template Document |
| fth | Forth Source Code |
| ftl | FreeMarker Template |
| ftlh | FreeMarker HTML Template |
| ftlx | FreeMarker XML Template |
| ftn | Fortran Source Code |
| ftr | Falcon Translation |
| ftt | Falcon Translation Template |
| ftx | WinDev HyperFileSQL Full-text Index |