| lef | LEN Exchange Format File |
| lef | EnCase Logical Evidence Data |
| len | Esko PlatePrep Len File |
| leo | Leo Editor Outline Data |
| lepf | Little Endian Prebuilt Format File |
| les | Mklesson Lesson File |
| les | TurboWin LES Data |
| lesshst | Less History File |
| lex | Microsoft Office Custom Dictionary |
| lexe | SciTE Data |
| lext | Olympus LEXT Measurement Export Data |
| lfa | Life Forms Studio Motions Data |
| lfb | Laserfiche Briefcase |
| lfe | Laserfiche Shortcut |
| lfnt | ReadyNAS Remote Folder Shortcut |
| lfp | IPRO LFP Data |
| lfs | Samsung Android Phone LFS File |
| lfv | Labassert Functional View Library |
| lg1 | OptionVue Portfolio Manager LGN Backup |
| lg2 | OptionVue Portfolio Manager LGN Backup |
| lg3 | OptionVue Portfolio Manager LGN Backup |
| lgb | Intuit QuickBooks Encrypted Login Data |
| lgb | PC LogBook Data |
| lgc | Microsoft Windows Application Log |
| lgd | Microsoft Windows Application Log |
| lge | BallStat League Data |
| lgen | PLINK Long-format Genotype File |
| lgf | Microsoft Windows Application Log |
| lgf | LeechGet FTP Queue |
| lgg | Microsoft Windows Application Log |
| lgh | Microsoft Windows Application Log |
| lgh | Intouch HMI Historical Log File |
| lgi | Multimedia Logic Data |
| lgl | Large Graph Layout Edge File |
| lgn | OptionVue Portfolio Manager Log Notes |