| 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 |
| ilht | Mac OS X Finder Internet HTTP Location |
| ilib | ClarisDraw Art Library |
| ilm | MotionTracking Illumination Correction Data |
| ilo | HP ILO Recorded Console Session |
| ilock | iData Lock Data |
| ilogicvb | Autodesk Inventor iLogic VB Script |
| ilp | Gurobi Optimizer Temporary Data |
| ilr | Unity License Request File |
| ils | RFM Instrument Line Shape File |
| ilt | SpectrILight III Saved Spectrum Binary Data |
| ilx | Interlex Vocabulary Data |
