| fwaction | Freeway Action |
| fwbackup | Freeway Backup |
| fwc | FWS Sonde Import Data |
| fwd | Bentley InRoads Survey Field Book |
| fwe | FWS Field Data |
| fwf | Bentley InRoads Survey Feature Table Data |
| fwl | Firewall Builder Library |
| fwn | FreeWave Network Data |
| fwr | Faceware Analyzer Tracking Data |
| fxb | Cubase FX Bank |
| fxf | IBM Endpoint Manager Action |
| fxn | Fast XML Notation Data |
| fxp | Cubase FX Program |
| fxt | MakeMusic Finale Script |
| fxv | SPSD/M FXV Data |
| fxye | GSAS Data |
| fyi | Concordance FYI Server Data |
| fz2 | JB BAHN Zoom2 Graphics |
| fz4 | JB BAHN Zoom4 Graphics |
| fza | Form Z Autosave File |
| fza | Fattz Announcement Header |
| fzb | Fritzing Binary |
| fzb | Form Z Backup File |
| fzbz | Fritzing Bundled Binary |
| fzh | Form Z Help Index |
| fzm | Fritzing Module |
| fzn | FlatZinc Modelling Language Data |
| fzp | Fritzing Custom Part |
| fzpz | Fritzing Bundled Part |
| fzy | LexisNexis Concordance Fuzzy Data |
| g-code | G-code Code |
| g01 | HEC-RAS Geometry File |
| g02 | HEC-RAS Geometry File |
| g03 | HEC-RAS Geometry File |
| g04 | HEC-RAS Geometry File |
