| ivm | Avaya Modular Messaging Voice Message |
| ivml | INDENICA Variability Modelling Language Data |
| ivs | Aircrack-ng Initialization Vector Data |
| ivt | Beyond 20/20 Multi-dimensional Table |
| ivw | i-Vocab World Array |
| ivwr | IntelliVIEW Offline Report Data |
| ivx | Beyond 20/20 Micro-data Extract File |
| ivy | Apache IVY Module Descriptor |
| iw | Chain Engineering Database |
| iw | IdleWild Screensaver File |
| iw2 | Information Workshop 2000 Data file |
| iwl | Incomedia WebSite X5 License Data |
| iwm | AimTech IconAuthor File |
| iwnew | Autonomy Interwoven iwdeploy Server Received File |
| iwold | Autonomy Interwoven iwdeploy Server Received File |
| iwt | Sunnysoft InterWrite Skin |
| iwxdata | iWorx LabScribe Data |
| ix | dtSearch Desktop Index |
| ix1 | Rebel Chess Data |
| ix2 | Corel WordPerfect Address Book |
| ixbrl | Sage iXBRL Data |
| ixc | ArcVIEW Geocode Coverage Index |
| ixe | IndeXExploit Index Data |
| ixf | Integration Exchange Format File |
| ixl | DB/TextWorks Database Indexed List |
| ixo | LightCycler v4 Experiment Data |
| ixr | XL Reporter Template |
| ixs | ArcVIEW Geocode Index |
| ixw | Pedigree Central Database Index |
| ixy | ISIS v2 Schematic Data |
| j3d | Atari Jaguar 3D Object |
| j3md | JMonkey Engine Material data |
| j64 | Virtual Jaguar ROM Image |
| jacksum | Jacksum Checksum Data |
| jaf | Just A Frequency Logger Backup Data |