| lad | Daylon Leveller Animation |
| laf | Essential Taceo License Activation File |
| lang | Skype Language File |
| lar | Liquid Audio Player Registration Data |
| las | Lidar Data Exchange Format File |
| las | Log ASCII Standard |
| lax | AnetHelpTool JavaHelp Viewer File |
| lay | Lightscape Layer File |
| lay | Rhino 3D Layer |
| lay | Pro/ENGINEER Layout |
| lay | ArchiCAD PlotMaker Layout |
| layout | Adobe Premiere Workspace Layout |
| layx | PTV VISSIM Vehicle Network Data |
| laz | LASzip Compressed Lidar Data |
| lbd | Life Balance Data File |
| lbe | Life Balance XML Exchange Data |
| lbg | dBASE IV Label Generator Data |
| lbk | ArchiCAD PlotMaker Layout Book |
| lbr | EAGLE Library File |
| lbv | T-Online Ob4hbci Layout Print File |
| 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 |
