| fkr | FKR Program Data File |
| fl | DRM Forward Lock |
| fl3 | Adobe Photoshop Flash 3D Document |
| fl7 | PCModWin MODTRAN Output Data |
| flame | Fractal Flames Data |
| flatpakref | Linux Flatpak Package Description |
| flatpakrepo | Linux Flatpak Repository Data |
| flb | FileMaker Pro Label Data |
| fld | 3D Fassade Plus Field Data |
| fld | WinFlash Flashcard Settings |
| flexolibrary | Final Cut Pro Library Database |
| flf | FLAMES License Data |
| flf | Microsoft Dynamics NAV License File |
| flg | MicroSim PCBoard Log Data |
| fli | Autodesk Animator Mask Data |
| flib | Foxit Reader Library |
| flic | Autodesk Animator Mask Data |
| flipchart | ActivInspire Flipchart |
| flk | Folder Lock Data |
| flka | Folder Lock FAT32 Portable Locker File |
| flkb | Folder Lock NTFS Portable Locker File |
| flkey | Fruity Loops Studio License Key |
| fln | XMap Flight Plan Data |
| flo | LightCycler v3 Experiment Data |
| flo | WRAP Inflow IN Records Data |
| float | ARIA Server Float Data |
| flow | Microsoft Expression SketchFlow Data |
| flp | ActivInspire Flipchart |
| flp | Fractal Explorer Landscape Project |
| flr | WinFlash Results File |
| fls | Creator Fault List File |
| fls | WinFlash Flashcard Source |
| flt | Carlson 2016 Triangulated Irregular Network Data |
| flt | OpenFlight Model Data |
| flt | WinFlash Compiled Test |
