| 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 |
| fw4 | Framework IV File |
| fwx | FoxWeb Script |
| fx | Microsoft DirectX D3D Effect |
| fxa | FaceFX Actor File |
| fxh | XNA Game Studio HLSL Header File |
| fxl | FaceFX Language File |
| fxml | JavaFX Interface Description |
| fxp | Visual FoxPro Compiled Program |
| fxpl | Adobe Flash FXP Library |
| gab | WinDev Skin Template |
| gambas | Gambas V2 Application |
| gar | GridGain Archive |
| gas | Atari Jaguar GPU Assembly Source |
| gb | Basic4GL Source Code |
| gb1 | Game Maker Backup File |
| gb2 | Game Maker Backup File |
| gbas | GLBasic Source Code |
| gbf | BASIS GUIBuilder Control Data |
| gbk | Embarcadero InterBase Database Backup |
| gbl | Visual Basic Global Declaration |
| gc1 | Golden Common Lisp 1.1 Source Code |
| gcda | Gcov Data File |
| gch | Precompiled C Header File |
| gcl | GNU Common Lisp Source Code |
| gcna | Gcov Compiled Output |