| ifn | IGOR Pro Formatted Notebook File |
| ifo | ImageForge Pro Graphic Object Layer Data |
| ifo | RSView Machine Edition Information Setup Data |
| ifol | Instant File Opener Data |
| ifp | KnowledgeMan Script |
| ifs | Ant Movie Catalog Script |
| ifs | FractInt IFS File |
| ifs | InfoSlips Package |
| ifs | OS/2 Warp Installable Filesystem Data |
| ift | BSL Inverse Fourier Transform Data |
| ift | IGOR Pro Formatted Notebook Template File |
| ifw | INTUS Terminal Firmware |
| ig | iSpy Event Data |
| igb | Google Earth Model File |
| igc | Anime List Builder Data |
| igd | TIBCO Spotfire Graph Definition |
| igl | inSORS Grid Layout File |
| igm | Indigo Material Data |
| igm | IOCOM Visimeet Data |
| igma | INTUS Terminal Graph Mask Archive |
| ign | Adobe RoboHelp Ignore List |
| ign | ICQ Ignore List |
| igq | Indigo Queue Data |
| igr | Igor Engraver Data |
| igs | Indigo Renderer Scene |
| igt | ImageGadget Template |
| igtheme | ImageGlass Theme |
| igtx | IGOR Pro Text |
| igv | Integrative Genomics Viewer Data |
| igw | Interactive Groundwater Modeling Data |
