| iid | Instantiated IED Description Data |
| iie | SimSystem IIe Emulator Data |
| iii | Know Your Stuff File |
| iil | Norton CleanSweep Installation Log |
| iis | Panasonic Camcorder IIS Metadata |
| iix | SDL Trados Translation Memory Index |
| ike | IKE-Scan Data |
| ikn | IKinema Rig Data |
| il3 | ParticleIllusion 3 Library |
| ild | ILDA Frames |
| ilda | ILDA Frames |
| ileaf | Interleaf Desktop |
| ilf | Alim Data File |
| ilg | LaTeX Index Generation Log |
| ilm | MotionTracking Illumination Correction Data |
| ilp | Gurobi Optimizer Temporary Data |
| ilr | Unity License Request File |
| ils | RFM Instrument Line Shape File |
| ilx | Interlex Vocabulary Data |
| im4m | IMG4 Signature Data |
| im4p | IMG4 Payload Data |
| ima | Zemax Image Surface Data |
| imap | IceWarp Mail Server IMAP Data |
| imb | IncrediMail Address Book |
| imd | Integration Manager Database |
| ime | IncrediMail Emotions Data |
| imesx | Microsoft Office IME Search Provider Definition |
| imf | IncrediMail Letter File |
| img | Magellan eXplorist Map Image |
| img3 | Apple iPhone IMG3 Data |
| img4 | Apple iPhone IMG4 Data |
| imh | IncrediMail Contacts Export Data |
| imi | Magellan eXplorist Map Image |
| imiss | PLINK Individual-based Missing Data Report |
| imk | IncrediMail License Key |