| fbr | BrainVoyager QX Fiber Coordinates Data |
| fbv | GrafNav Exported Binary Values Data |
| fbwinsx | FileBoss Internal Data |
| fc1 | FCEUX Saved State |
| fc2 | FCEUX Saved State |
| fc2 | Poser Face Data |
| fc3 | FCEUX Saved State |
| fca | Omnis Web Client Form Cache |
| fcat | Fact200 Categories Data |
| fcc | SiteMinder Forms Credential Collector Data |
| fcd | PFS First Choice Database |
| fcdot | ABBYY FlexiCapture Engine Document Definition |
| fcf | XtalView Xfit Phase Data |
| fcg | GAUSS Engine Compiled Gauss Data |
| fch | Gaussian Formatted Checkpoint File |
| fchc | Fetch Cache Data |
| fchk | Gaussian Formatted Checkpoint File |
| fci | Erosion 3D Inflow Table |
| fci | Fiery Clone Tool Image |
| fciv | Microsoft File Checksum Integrity Verifier Data |
| fcl | FidoCAD Library |
| fcm | Brother ScanNCut Data |
| fcm | Factory Commander Model Data |
| fcm | FCEUX FCE-Ultra Capture Movie |
| fcm | FidoCAD Macro Data |
| fcod | Adobe PageMaker Filter Data |
| fcp | FLAMES Checkpoint Restart Data |
| fcpcache | Final Cut Pro Cache Data |
| fcpevent | Final Cut Pro Event Data |
| fcpxdest | Final Cut Pro Share Destination Data |
| fcs | Canon ZoomBrowser EX Data |
| fcs | FCEUX Saved State |
| fcs | Flow Cytometry Standard Data |
| fcs | Rapidform Polygon Faces Data |
| fcst | Delft-FEWS Forecast Data |
