| iswp | iTunes iOS Software Update Data |
| is_ | Compressed ISP File |
| it3 | Internet Timer 3 Log |
| itb | iTunes Database |
| itd | SDL Intermediate Translation Document |
| itd | IRIT 3D Data |
| itdb | iTunes Database |
| ite | iTunes Extras |
| item | DM Genie Item Data |
| itemdata-ms | Windows 8 Start Screen Item Data |
| ith | InTether Receiver Package |
| itk | Insight Segmentation and Registration Toolkit Data |
| itl | iTunes Library File |
| itld | Infoworx Translation Library Database |
| itlp | iTunes LP Album Data |
| itm | iThink Model |
| itm | DMDX Item Data |
| itmx | iThink Model Data |
| itn | TomTom Route Data |
| itp | GROMACS Include Topology |
| itp | e-Record Data File |
| itpc | iTunes Podcast Link |
| itr | iThink Runtime |
| itss | Microsoft InfoTech Storage System File |
| itt | IconTweaker Theme |
| itu | Sheffield Dictionary Data |
| itv | Nostalgia Emulator Intellivision ROM |
| itw | InTouch With Database |
| itx | IGOR Pro Text File |
| itx | FileNet ITX Form Template |
