| ldm | Sybase PowerDesigner Logical Data Model |
| ldmt | Likno Drop-Down Menu Trees Data |
| ldp | Active Directory Exported LDAP Data |
| ldsx | STAAD Advanced Concrete Design Cases and Combinations Data |
| ldt | Oracle Generic Loader Data File |
| ldt | EULUMDAT File |
| ldy | RAMAS Landscape Data |
| leases | DHCP Server Leases Data |
| led | AIBO LED File |
| lef | LEN Exchange Format File |
| lef | EnCase Logical Evidence Data |
| lel | LayoutEditor Library Data |
| len | Esko PlatePrep Len File |
| lens | Autodesk Stitcher Camera Profile Data |
| leo | Leo Editor Outline Data |
| lepf | Little Endian Prebuilt Format File |
| les | Mklesson Lesson File |
| les | LayoutEditor Schematic Data |
| les | TurboWin LES Data |
| lesshst | Less History File |
| lex | SmartWare Dictionary Data |
| 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 |
| lfi | Datcom+ Linear Function Interpolation Data |
| lfnt | ReadyNAS Remote Folder Shortcut |
| lfp | IPRO LFP Data |
| lfs | Samsung Android Phone LFS File |
| lfv | Labassert Functional View Library |
| lg0 | IBM Tivoli Monitoring Log |
| lg1 | OptionVue Portfolio Manager LGN Backup |
| lg1 | ScadaWorks ScadaBuilder Log |