| lon | Aquaterra Longitudinal Profile Data |
| look | Adobe SpeedGrade Look |
| looklibrary | Corel Painter Looks Library |
| loop | Apple Soundtrack Pro Loop Data |
| loov | SmadAV Virus Definitions |
| lop | MasterCook Layout Data |
| lov | SAP Business Objects LOV File |
| loxplan | Loxone Miniserver Program |
| lo_ | Microsoft SMS Previous Log Data |
| lp | FlexRip Data |
| lp | LaTeX Drawing Data |
| lp | Lightscape Preparation File |
| lp4 | 36-Image Converter Language Data |
| lp7 | LP7 Digitally Signed Data |
| lpa | LPA View Data |
| lpd | Helix Nuts and Bolts File |
| lpdb | Librarian Pro Database |
| lpk | Tecplot Layout Package |
| lpl | LPL Model |
| lpm | WonderBit Life Photo Maker Data |
| lpmd | LPMD Molecular Data |
| lpn | LVPLAN Data |
| lps | Bryce 7 Leaf Shape |
| lpsx | LARSA 4D Section Database |
| lpt | PDP-10 Printer Output Data |
| lpt | TrialDirector Load Data |
| lpv | Lasergraph DSP Laser Show Preview Data |
| lpw | IRIS Laserforms Lforms Data |
| lpx | LaTeXPiX Script |
| lqa | LabQuest 2 Automatic Update |
