| i2c | IBM Voice Type Languages Newuser Data |
| i2g | Intergeo I2G Geometric File |
| i2s | Green Kenue 2D Lineset Data |
| i32 | LabVIEW I32 Data |
| i3dm | Cesium Instanced 3D Tiles Data |
| i3ml | I3ML Data |
| i3s | Green Kenue 3D Lineset Data |
| i5d | IUCLID5 XML Backup |
| i5s | IUCLID5 Compressed Backup |
| i5z | IUCLID5 Export File |
| i61 | Nokia 6100 Icon Data |
| ia1 | Infinite Algebra 1 Data |
| ia2 | Infinite Algebra 2 Data |
| ia6 | IApproach Work Data |
| iab | Iomega Automatic Backup Data |
| iab | DB/TextWorks Image Annotation List Backup |
| iad | Symantec Patch Management Solution Data |
| iadaction | iAd Producer Plugin Action Template |
| iadclass | iAd Producer Plugin Class Description |
| iadcomponent | iAd Producer Component |
| iadpage | iAd Producer Page Template |
| iadstyle | iAd Producer Style Template |
| iak | Mail.dat Information Access Key |
| ial | Microsoft SharePoint List Activity Data |
| ias | Intermodulation Analysis System Data |
| iati | International Aid Transparency Initiative Data |
| iaw | ImageAMMO Wrapper |
| ib | Embarcadero InterBase Database |
| ibadr | IsoBuster Address Data |
| ibak | Password Safe Intermediate Backup Archive |
