| lbg | dBASE IV Label Generator Data |
| lbk | ArchiCAD PlotMaker Layout Book |
| lbr | EAGLE Library File |
| lbv | T-Online Ob4hbci Layout Print File |
| lbw | CCP Log Server Log |
| lc | L0phtCrack Password Database |
| lcb | Kodak EasyShare Album List |
| lcd | Abbyy FineReader Dictionary File |
| lcf | ArchiCAD Library Container File |
| lcl | LISCAD Lite Database |
| lcm | Lipikar Custom Map |
| lcn | Trymedia License Data |
| lcp | FARSITE Landscape Data |
| lcs | L0phtCrack Password Database |
| lcs | Alstom MMS LCS Compiler Report |
| lcs | Light-O-Rama Compressed Sequence File |
| lcv | Radio Mobile Land Cover Data |
| lcx | LC Model |
| ld | MoTeC Telemetry Log |
| ld1 | dBASE IV Overlay File |
| ld2 | Lingoes Compiled Dictionary |
| ldata | JSim Line Data Format |
| ldb | Microsoft Access Database Lock |
| ldb | Sybase PowerDesigner Logical Data Model Backup |
| ldc | Steuer 2001 Data File |
| ldd | Laser Dispatch Data File |
| lde | Veeam Explorer Exported Data |
| ldf | Microsoft SQL Server Transaction Log |
| ldf | LDAP Data Interchange Format File |
| ldf | LogPlot LogDesign File |
