| gqt | GQT Index |
| gqu | BI/Query User Data Model |
| gr | PDFgetX3 GR File |
| gr3 | Pathloss Network Data |
| gr4 | Pathloss Network Data |
| gr5 | Pathloss Network Data |
| gr7 | Simatic S7 Graph Data |
| gr96a | GROMOS96 A Chemical Modeller Input Data |
| gr96n | GROMOS96 NM Chemical Modeller Input Data |
| gradients | Corel Painter Gradient Library |
| grads | PINGO GrADS Data |
| gram | CMUSphinx Grammar Data |
| gramps | GRAMPS XML Data |
| graph | Mascopt Graph Data |
| grc | Affymetrix Grid Control File |
| grd | ElmerGrid Mesh Definition File |
| grd | RFM Irregular Spectral Grid |
| grdb | GRAMPS Database |
| gre | GRETEP Data |
| greenshot | Greenshot Data |
| grfx | GraphStudioNext XML Graph Data |
| grh | ILWIS Graphs Data |
| gri | Petrosys Grid Data |
| grib | Gridded Binary Data |
| grid | GridMove Grid Template |
| grk | Gradekeeper Class Gradebook |
| grldr | GRUB4DOS Internal Loader Data |
| grm | PLINK GCTA Text Relationship Matrix |
| group | Unix Filesystem Group Quota Data |
| groups | WebMoney Keeper CLASSIC Group Data |
| grov | Reason Regroove Data |
| growlregdict | Growl Registration Ticket Data |
| growlticket | Growl Notification Data |
| grp | GenePattern Gene Set Group File |
| grp | GameExchange2 Scene List |