| ibu | MariaDB InnoDB Undo Log |
| ibv | IGOR Pro Binary Variable File |
| ibw | IGOR Pro Binary Wave File |
| ibx | Interscope BlackBox File |
| ibz | MySQL InnoDB Database Table Compressed Backup |
| ic | Sony Ericsson Icon Pack |
| ic0 | HSPICE Initial Conditions Data |
| ic4 | SADiE Interchange Data |
| ica | BrainVoyager QX Independent Component Analysis Data |
| icalevent | iCal Event Data |
| icaltodo | iCal To Do List |
| icbu | iCal Backup |
| icc | ICC Profile |
| icc | IconUtils Icon Collection |
| ice | CoolTalk Invitation Data |
| icg | Image Comparer Database |
| ichat | iChat Saved Log |
| icl | ArtIcons Icon Library |
| icl | Mail.dat International Container Label File |
| icm | Image Color Matching Profile |
| icm | Integrated Climatic Model Data |
| icms | RagTime Data |
| icn | OpenFlight Model |
| icns | Mac OS X Icon Resource File |
| iconbox | IconBox Data |
| iconfig | iConfig Data |
| iconset | Mac OS X Icon Resource File |
| icontainer | CandyBar iContainer Data |
| icq | ICQ Archive Data |
| icr | Impromptu Content Report |
| icsalarm | iCal Alarm Data |
| ict | Cadence ASCII Interconnect Technology File |
| icursorfx | iCursor Effect |
| icx | Windows CE Remote Call Profiler Summary View |
| icxs | iTunes Internal Data |