| lqr | Squeezed LBR Archive |
| lrp | Linux Router Project Package |
| lrz | Long Range Zip Compressed Archive |
| lxv | Lexar Secure II Encrypted Archive |
| lz | Lzip Compressed File |
| lz4 | LZ4 Compressed Data |
| lzb | LZB Archive |
| lzg | LZG Compressed Data |
| lzh | LHarc Compressed Archive |
| lzip | Lzip Compressed File |
| lzj | Atari Jaguar LZSS Compressed Data |
| lzm | Slax Module |
| lzma | LZMA Compressed File |
| lzo | LZOP Compressed File |
| lzop | LZOP Compressed File |
| lzr | Crunched LBR Archive |
| lzss | LZSS Compressed Data |
| lzw | LZW Compressed Amiga Archive |
| lzx | Amiga LZX Compressed Archive |
| m | Mathematica Package |
| mabk | Lenovo MOTO Smart Assistant Backup Data |
| maff | Mozilla Archive Format File |
| mb2 | McMyAdmin 2 Backup Archive |
| mbkp | Memeo Instant Backup Archive |
| mcaddon | Minecraft Addon Package |
| mcb | McMyAdmin Backup Archive |
| mcpack | Minecraft Resource Pack |
| mdbackup | iPhone Data Backup |
| mddata | iPhone Backup Archive |
| meo | MEO Encrypted Archive |