| iset | ARToolKit NFT Image Set |
| isf | InfoAsset Manager Snapshot Data |
| isg | HSC Chemistry Solgasmix Solver Data |
| ish1 | Animation-ish Wiggledoodle-ish Document |
| ish2 | Animation-ish FlipBook-ish Document |
| ish3 | Animation-ish Advanced-ish Document |
| isi | Web of Science Databases Output |
| isk | Druvaa inSync Client Key |
| isl | Inno Setup List |
| ism | ESI ITI SimulationX Encrypted Model |
| ism | ISAM Database |
| isml | IIS Smooth Streaming Publishing Point Definition |
| iso | Cimagraphi ISO CAD Data |
| isoe | ISO Builder Data |
| ispc | Image Surfer Pro Collection |
| ispd | Shimadzu LabSolutions IR Data |
| isr | InstallShield Uninstall Information |
| iss | Caseware IDEA IDEAScript |
| ist | IsoStar Library of Intermolecular Interactions Data |
| istg | Imagine Staging File |
| istr | IsoStar Library of Intermolecular Interactions Data |
| isu | CRiSP Harvest ISU Data |
| isv | IDL iTools Saved State |
| isw | Intuit Statement Writer Data |
| isw | ZoneAlarm ForceField Data |
| iswp | iTunes iOS Software Update Data |
| is_ | Compressed ISP File |
| it3 | Internet Timer 3 Log |
| ita | Unreal Engine Italian Language Data |
| itb | iTunes Database |
| itd | IRIT 3D Data |
| itd | SDL Intermediate Translation Document |
| itdb | iTunes Database |
| ite | iTunes Extras |
| item | DM Genie Item Data |
