| 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 |
| lqf | LeechFTP Saved Queue |
| lqm | Liquid Audio Master Data |
| lqn | CoWolf Layered Queuing Network Data |
| lqp | Liquid Audio Player Passport Data |
| lqs | Libvirt Qemu Saved Data |
| lqu | LeapFTP Queue Data |
| lra | HPE LoadRunner Analyzed Results |
| lrcat | Adobe Photoshop Lightroom Catalog |
| lrcx | KwMusic Data |
| lrdata | Adobe Photoshop Lightroom Data |
| lrdb | Adobe Photoshop Lightroom 1.0 Database |
| lrl | SmartWare Local Resource Library |
| lrm | Microsoft Encarta Class Server Learning Resource Module |
| lrpreview | Adobe Photoshop Lightroom Preview |
| lrq | GEAR License Request File |
| lrr | HPE LoadRunner Raw Results |
| lrreg | Adobe Photoshop Lightroom License Data |
| lrs | Corel WordPerfect Language Data |
| lrs | Daylon Leveller Rendition Style |
| lrs | HPE LoadRunner Scenario Data |
| lrsr | MODELLER Loop Modeling Restraints Data |
| lrtemplate | Adobe Photoshop Lightroom Template |
| lrtoolkit | Adobe Photoshop Lightroom Toolkit Data |
| ls | Guitar Rig Loop Machine Data |
| ls | LayaAir Scene Data |
| ls | Lightscape Solution File |
| ls | Lightwave 3D LScript Data |
| ls2 | LabSat 2 Data |
| ls3 | Band-in-a-Box Third-Party Styles |
| ls3 | Magic Bullet Looks Package |
| ls3w | LabSat 3 Wideband Data |
| ls8 | LISREL 8 Syntax Data |
| lsa | HCL Domino Designer Agent |
| lsa | Lightscape ASCII Data |
| lsa | Lotus Domino Agent Script |
| lsb | Lightscape Binary Data |
| lsc | Light-O-Rama Schedule File |
| lsc | LOGO!Soft Comfort Circuit File |
| lsdx | Apex Z3 Lighthouse Secure Data |
| lse | Oracle Utilities Load Analysis Input |
| lsf | LISREL System Data |
| lsg | LimeSurvey Group Structure XML |
| lsgfx | Livestream Studio Graphics Data |
| lsi | SAP Business Objects Local Security Information File |
| lsim | LogicSim Circuit |
| lsl | LightScribe Label |
| lslang | Ad-Aware Language Data |
| lslibrary | LittleSnapper Library Package |
| lsn | MakeMusic Finale Lesson |
| lso | BHV Tonstudio Platin Data |
| lsopt | LS-OPT Data |
| lsp | Audacity LSP Data |
| lsp | LANsurveyor Poll List |
| lsq | CRYSTALS Isotropic Refinement Data |
| lsq | PaleoMag Least Squares Data |
| lsq | ZOOM MRS-802 Phrase Loops Data |
| lsr | LANsurveyor Report |
| lsrx | ApexZ Certification Report |
| lssave | Memory Hacking Software Saved Memory Data |
| lst | Adobe Font List |
| lst | ALSee List Data |
| lst | BPM Studio Playlist |
| lst | Concordance Word List Data |
| lst | E-Sword v8 Verse List |
| lst | Family Tree Maker Error Log |
| lst | Holux MapShow Map List |
| lst | IMail Server List Server Mail |
| lst | Ingres Dump List Data |
| lst | Kaspersky Anti-virus Blacklist |
| lst | LightScribe Label Template |
| lst | Now Contact List Template |
| lst | Oracle Database Spool Data |
| lst | Orchida Knitting System List Data |
| lst | PTC Creo Feature List Data |
| lst | SAS Procedure Output |
| lst | SignIQ Field List |
| lstmf | Tesseract OCR lstmtrainer Data |
| lstx | E-Sword v9 Verse List |
| lsu | LANsurveyor Map |
| lsw | DxLibraryStudio Workspace |
| lsw | Technics SX-KN6000 Current Panel Data |
| lsz | Learning Score Zipped Data |
| lsz | Litestep Theme File |
| lt | Moltemplate Data File |
| lt2 | Poser Light Data |
| lta | Monolith LithTech Game Engine Data |
| ltc | Linguistic Tree Constructor Data |
| ltcx | Linguistic Tree Constructor XML Data |
| ltd | HPE Library and Tape Tools Support Ticket |
| ltd | LivingTime Data File |
| ltf | Frogans Short-cut |
| ltf | Laser App Temp Form Data |
| lth | Roxio Label Creator Style Data |
| lthmb | Adobe Presenter Audio Thumbnail |
| ltl | DIALux Luminaire Data |
| ltl | TwoTowers LTL Formula |
| ltm | Autodesk Simulation Mechanical Load Case Number Text |
| ltm | LiteMail Database |
| ltn | Carlson Survey Lot Network File |
| ltn | LinkTreeNotes Data |
| ltpl | Insight II Layout Template Data |
| ltt | HP Library and Tape Tools Log |
| ltz | Poser Compressed Light Data |
| lu | ThoughtWing Library Unit |
| luacodec | Reason Remote Lua Codec Data |
| luar | UltraDefrag Lua Report |
| lucidcolorset | Lucid Colorset Data |
| lucs | Amaya Tools Data |
| lucy | HTC Scribble Note |
| lud | ABBYY Lingvo Dictionary User Dictionary |
| lud | Altair FEKO LU-decomposition Data |
| lud | CARE-S InfoWorks Land Use Data |
| lue | Norton LiveUpdate Log |
| luh | ARINC 615A Load Upload Header |
| lum | DB-MAIN Binary Method Definition Data |
| lum | Luminous Schedule File |
| luminar | Luminar 4 Catalog Database |
| lunch | Lunchbox Battles Data |
| lup | ARINC 615A Load Upload Part |
| lup | OzWin Library Update File |
| lus | ARINC 615A Load Upload Status |
| lux | Spectramap Database |
| luz | Spectramap Data |
| lvc | Alstom MMS LVC Compiler Report |
| lvclass | LabVIEW Class Library |
| lvd | Avery LabelPro Design Document |
| lve | DanceScore Live Data |
| lvg | ListViewGenerator Data |
| lvix | Lightworks Index File |
| lvl | Android Motion Video Thumbnail File |
| lvl | Samsung Galaxy Video Thumbnail Cache |
| lvlib | LabVIEW Project Library |
| lvlibp | LabVIEW Packed Project Library |
| lvs | Daylon Leveller Selection Mask |
| lw | Lightwave 3D Binary Data |
| lw2 | Lightwright Show Data |
| lw4 | Lightwright 4 Data |
| lw5 | Lightwright 5 Data |
| lwa | LightWorks Archive |
| lwa | Lightwright Automated Action Data |
| lwac | Likno Web Accordion Builder Data |
| lwav | eXtendable Wad Editor LWAV Data |
| lwbm | Likno Web Button Maker Data |
| lwd | Lightworks Data File |
| lwg | Autodesk LandXplorer Terrain Data |
| lwk | LonghornMax Data |
| lwk | Siemens NX Graphics Data |
| lwlo | Lightwave 3D Layered Object |
| lwmw | Likno Web Modal Windows Builder Data |
| lwo | Tstream Editor Translation Package |
| lwp | Lightwright Power Phase Layout Data |
| lwpp | Live Wallpaper for Mac Theme Data |
| lwq | SWAT Lake Water Quality Input Data |
| lwsc | Likno Web Scroller Builder Data |
| lwt | Lightwright Attribute List |
| lwtb | Likno Web Tabs Builder Data |
| lwtp | LimeWire Theme Pack |
| lwtt | Likno Web Tooltips Builder Data |
| lwx | Lightwright Database |
| lwx | WinTherm RT Radiation Exchange Factors Data |
| lwy | Lightwright Library |
| lx | LPEX Customization Command Profile |
| lx3 | Lounge Lizard EP3 Exchange Data |
| lxa | Microsoft Speech Lexicon |
| lxd | eDictionary Reader Dictionary Data |
| lxd | Lexacom Data |
| lxf | Compressed LEN Exchange Format File |
| lxg | LEGO CAD Exchange Data |
| lxk | COREX Lexicon Link-up Data |
| lxk | Proteus License Key |
| lxl | LPEX Load Macro |
| lxl | Luxology Modo Single-layer Mesh Data |
| lxm | Lexacom Mobile Dictation Data |
| lxp | MODO Luxology Asset File |
| lxplot | LXFree Plot File |
| lxq | DAZ Studio Frame List Data |
| lxs | LPEX Save Macro |
| lxt | Icarus Verilog interLaced eXtensible Trace |
| lxu | LPEX User Profile |
| lxw | Lexacom Talk and Type Dictation Data |
| lxx | LXFree XML Plot |
| ly2 | EAGLE Inner Signal Layer GERBER Data |
| lyc | Renault R-Link Internal Data |
| lyf | LayoutFAST Layout Data |
| lyr | DataCAD Layer Data |
| lys | DataCAD Layer Control Data |
| lyt | Adminsoft Accounts Document Layout |
| lyt | DESQview Layout Data |
| lyt | Intuit TurboTax Install Log File |
| lyt | MetaCAM Layout Data |
| lyt | Thermo Xcalibur Layout Data |
| lyt | vanBacsco Karaoke Player Skin |
| lzf | Autodesk 3D Studio MAX Lens Effect Flare Data |
| lzk | LoizziTimeControl Database |
| lzt | HPE Library and Tape Tools Compressed Support Ticket |
| m | Maple Internal Format File |
| m00 | ComputerEyes Animation Data |
| m01 | MicroStation Modification User Resource File |
| m06 | Microsoft Money 98 Backup Data |
| m07 | Microsoft Money 99 Backup Data |
| m09 | Microsoft Money 2001 Backup Data |
| m0d | Malete Database Metadata |
| m1 | Juki AMS Embroidery Data |
| m10 | Microsoft Money 2002 Backup Data |
| m11 | Microsoft Money 2003 Backup Data |
| m12 | Microsoft Money 2004 Backup Data |
| m12 | Schiller Medilog 12ch ECG Raw Data |
| m14 | Microsoft Money 2005 Backup Data |
| m15 | Microsoft Money 2006 Backup Data |
| m16 | Microsoft Money 2007 Backup Data |
| m1c | IBM Voice Type Languages Newuser Data |
| m21 | AXMEDIS MPEG21 Data |
| m25 | Symantec Endpoint Protection Manager Data |
| m29 | Turbo Smetchik M29 Data |
| m2d | HTC Manila 2D Skin |
| m2d | SNMP v2c MIB Data |
| m2dct | Manila 2D for Windows Mobile Skin Data |
| m2f | Maxthon 2 Browser Filter |
| m2l | Maxthon 2 Language Pack |
| m2p | GROMACS Mat2PS Data |
| m2p | Maxthon 2 Browser Plugin |
| m2r | Micromuse Mib2Rules Data |
| m2s | Maxthon 2 Browser Skin |
| m2u | Maxthon 2 Browser Layout Data |
| m3d | Corel MOTION 3D Scene |
| m3d | DIALux 3D Model Data |
| m3d | DJ Mix Pro Database |
| m3r | Autodesk Moldflow 3D Fill+Pack Restart File |
| m3x | MAGIX Digital Foto Maker PhotoCD Playlist Data |
| m4d | Sage MAS 90 Data File |
| m4p | Sage MAS 90 Program File |
| m4t | Sage MAS 90 Table File |
| m5p | MachFive Preset Data |
| m64 | Bitdefender M64 Data |
| m64 | Mupen64 Movie Capture |
| m6b | Speedtronic Mark VI Data |
| m75 | QuickTime Player M75 Data |
| m77t | GEODAS MGD77T Data |
| m7a | MapKing Map Data |
| m7c | Yamaha M7CL Digital Mixing Console Data |
| m98 | Nokia Mediamaster 9800S Satellites Data |
| ma3 | Harvard Graphics 3.0 Macro |
| ma4 | Vector NTI DNA Archive |