| 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 | Micrografx Picture Publisher Filter |
| flt | OpenFlight Model Data |
| flt | WinFlash Compiled Test |
| fltr | XTND Filter |
| flu | WinFlash Flashcard Source (new) |
| flw | Fluke LinkWare Database |
| flwa | Folder Lock Wallet File |
| flx | DataFlex Compiled Binary |
| flx | Flexstor Database |
| flx | MODTRAN FLX Output File |
| flxdato | OnScale Binary Results Data |
| flxext | OnScale Extrapolation Data |
| flxffl | OnScale Free Field Data |
| flxhst | OnScale Binary History Data |
