| xsa | XelaSoft Archive |
| xz | XZ Compressed File |
| xzm | Porteus Module |
| yar | YAK Compressed Archive |
| ybs | YBS Compressed Archive |
| yc | YAC Compressed |
| yep | Yamaha Expansion Pack |
| yz | YAC Compressed |
| yz1 | DeepFreezer Archive |
| z | Compressed File |
| z00 | InfoZIP ZipSplit Splitted ZIP Archive |
| z01 | WinZip First Split Zip |
| z01 | InfoZIP ZipSplit Splitted ZIP Archive |
| z02 | WinZip First Split Zip |
| z02 | InfoZIP ZipSplit Splitted ZIP Archive |
| z03 | WinZip First Split Zip |
| z03 | InfoZIP ZipSplit Splitted ZIP Archive |
| z04 | InfoZIP ZipSplit Splitted ZIP Archive |
| z04 | WinZip First Split Zip |
| z05 | InfoZIP ZipSplit Splitted ZIP Archive |
| z05 | WinZip First Split Zip |
| z96 | Microsoft Bookshelf 96 Update Package |
| zac | Zaurus Archive |
| zat | MSN Gaming Zone Data File |
| zbk | Zarafa Backup Archive |
| zet | ZET Compressed Archive |
| zfc | Back4Win Backup Archive |
| zfsendtotarget | Windows Zipped Folder |
| zfx | ZFX Archive |
| zgz | Zimbra Compressed Package |
| zip | ZIP Archive |
| zipe | Minecraft ZIPE Archive |
| zipx | WinZIP ZIPX Archive |
| zl | Zlib Compressed Data |
| zlib | Zlib Compressed Data |