| gtfs | General Transit Feed Specification Data |
| gth | BibExcel GTH Data |
| gth | IBM Lotus Domino Document Manager Gatherer Data |
| gthr | Microsoft SharePoint Portal Server Gather Log |
| gti | GT STRUDL Geometry Data |
| gtl | Gerber Top Layer Data |
| gtm | CFX Mesh File |
| gtm | GreekToMe Translation |
| gto | Gerber Top Overlay Data |
| gtp | Gerber Top Paste Mask Data |
| gtr | GenePattern Gene Tree File |
| gts | Gerber Top Solder Mask Data |
| gts6 | Topcon Link GTS-6 Raw Data |
| gts7 | Topcon Link GTS-7 Raw Data |
| gtw | Gen-Trix Studio Model |
| gtxlng | GearTrax Language Data |
| gty | MANTECH Tray Editor Gilson Tray Data |
| gui | GUI Design Studio Design |
| guides | xScope Guides Data |
| guikit | Shapeshifter Theme |
| gus | XMVB Orbital Guess Data |
| gvar | PLINK Genetic Variant File |
| gvd | Gladinet Cloud Data |
| gvf | Genome Variation Format Data |
| gvfx | Microvellum Global File |
| gvs | GuitarVision Data |
| gw | SWAT Groundwater Input Data |
| gwa | AMAPstudio Geometry with Attributes Data |
| gwc | Groundspeak Compiled Wherigo Cartridge |
| gwd | Gear Watch Designer Data |
| gwg | OxMetrics Graphics Data |
| gwl | Groundspeak Wherigo Cartridge Log |
| gws | Groundspeak Wherigo Save File |
| gwt | AquaCrop Groundwater Data |
| gwt | GeoDa Distance Weights Data |