| igq | Indigo Queue 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 |
| iha | Proficy Historian Archive |
| ihc | Proficy Historian Configuration |
| ihs | Bink Inbound History Data |
| ihw | IN-HEH Timeline Workspace |
| ihx | IN-HEH Timeline Database |
| ii | IconWorkshop Extended Information |
| iic | ISIS Initial Conditions Data |
| iid | Instantiated IED Description Data |
| iie | SimSystem IIe Emulator Data |
| iif | Shana Informed Filler Interchange Document |
| iii | Know Your Stuff File |
| iil | Norton CleanSweep Installation Log |
| iis | Panasonic Camcorder IIS Metadata |
| iix | SDL Trados Translation Memory Index |
| ijf | IDIS Job Data |
| ijg | Independent JPEG Group Related Data |
| ike | IKE-Scan Data |
| iklax | AirParrot Media Data |
| ikn | IKinema Rig Data |
| il3 | ParticleIllusion 3 Library |
| ilabel | iData 3 Template Label Data |
| ild | ILDA Frames |
| ilda | ILDA Frames |
| ileaf | Interleaf Desktop |
| ilf | Alim Data File |
| ilg | LaTeX Index Generation Log |
| ilg | LinkOne Internal Data |
| ilg | MakeIndex Error Log |
