| ldc | Steuer 2001 Data File |
| ldd | Laser Dispatch Data File |
| lde | Veeam Explorer Exported Data |
| ldf | LDAP Data Interchange Format File |
| ldf | LogPlot LogDesign File |
| ldf | Microsoft SQL Server Transaction Log |
| ldf | Lingoes Dictionary Source |
| ldfx | LogPlot LogDesign XML File |
| ldg | TIBCO Business Studio Ledger Data |
| ldi | LDAP Data Interchange Format File |
| ldif | LDAP Data Interchange Format File |
| ldk | Larson Davis System 824 Firmware Authorization Data |
| ldl | Paradox Delivered Library |
| 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 | LayoutEditor Schematic Data |
| les | Mklesson Lesson File |
| les | TurboWin LES Data |
| lesshst | Less History File |
| lex | SmartWare Dictionary Data |
| lex | Microsoft Office Custom Dictionary |