Text Files

.docMicrosoft Word Document
.docxMicrosoft Word Open XML Document
.logLog File
.msgOutlook Mail Message
.pagesPages Document
.rtfRich Text Format File
.txtPlain Text File
.wpdWordPerfect Document
.wpsMicrosoft Works Word Processor Document

Data Files

.blgWindows Binary Performance Log File
.csvComma Separated Values File
.datData File
.efxeFax Document
.keyKeynote Presentation
.ppsPowerPoint Slide Show
.pptPowerPoint Presentation
.pptxPowerPoint Open XML Presentation
.sdfStandard Data File
.vcfvCard File
.xmlXML File

Audio Files

.aacAdvanced Audio Coding File
.aifAudio Interchange File Format
.iffInterchange File Format
.m3uMedia Playlist File
.midMIDI File
.mp3MP3 Audio File
.mpaMPEG-2 Audio File
.raReal Audio File
.wavWAVE Audio File
.wmaWindows Media Audio File

Video Files

.3g23GPP2 Multimedia File
.3gp3GPP Multimedia File
.asfAdvanced Systems Format File
.asxMicrosoft ASF Redirector File
.aviAudio Video Interleave File
.flvFlash Video File
.movApple QuickTime Movie
.mp4MPEG-4 Video File
.mpgMPEG Video File
.rmReal Media File
.swfFlash Movie
.vobDVD Video Object File
.wmvWindows Media Video File

3D Image Files

.3dmRhino 3D Model
.max3ds Max Scene File

Raster Image Files

.bmpBitmap Image File
.gifGraphical Interchange Format File
.jpgJPEG Image File
.pngPortable Network Graphic
.psdAdobe Photoshop Document
.pspimagePaintShop Photo Pro Image
.thmThumbnail Image File
.tifTagged Image File
.yuvYUV Encoded Image File

Vector Image Files

.aiAdobe Illustrator File
.drwDrawing File
.epsEncapsulated PostScript File
.psPostScript File
.svgScalable Vector Graphics File

Page Layout Files

.inddAdobe InDesign Document
.pctPicture File
.pdfPortable Document Format File
.qxdQuarkXPress Document
.qxpQuarkXPress Project File
.relsOpen Office XML Relationships File

Spreadsheet Files

.wksWorks Spreadsheet
.xlsExcel Spreadsheet
.xlsxMicrosoft Excel Open XML Spreadsheet

Database Files

.accdbAccess 2007 Database File
.dbDatabase File
.mdbMicrosoft Access Database
.pdbProgram Database
.sqlStructured Query Language Data

Executable Files

.appMac OS X Application
.batDOS Batch File
.cgiCommon Gateway Interface Script
.comDOS Command File
.exeWindows Executable File
.jarJava Archive File
.pifProgram Information File
.vbVBScript File
.wsfWindows Script File

Game Files

.gamSaved Game File
.nesNintendo (NES) ROM File
.romN64 Game ROM File
.savSaved Game

CAD Files

.dwgAutoCAD Drawing Database File
.dxfDrawing Exchange Format File
.plnArchiCAD Project File

GIS Files

.gpxGPS Exchange File
.kmlKeyhole Markup Language File

Web Files

.aspActive Server Page
.cerInternet Security Certificate
.csrCertificate Signing Request File
.cssCascading Style Sheet
.htmHypertext Markup Language File
.htmlHypertext Markup Language File
.jsJavaScript File
.jspJava Server Page
.phpHypertext Preprocessor File
.rssRich Site Summary
.xhtmlExtensible Hypertext Markup Language File

Plugin Files

.8biPhotoshop Plug-in
.pluginMac OS X Plug-in
.xllExcel Add-In File

Font Files

.fntWindows Font File
.fonGeneric Font File
.otfOpenType Font
.ttfTrueType Font

System Files

.cabWindows Cabinet File
.cplWindows Control Panel
.curWindows Cursor
.dllDynamic Link Library
.dmpWindows Memory Dump
.drvDevice Driver
.lnkFile Shortcut
.sysWindows System File

Settings Files

.cfgConfiguration File
.iniWindows Initialization File
.keychainMac OS X Keychain File
.prfOutlook Profile File

Encoded Files

.binMacbinary Encoded File
.hqxBinHex 4.0 Encoded File
.mimMulti-Purpose Internet Mail Message File
.uueUuencoded File

Compressed Files

.7z7-Zip Compressed File
.debDebian Software Package
.gzGnu Zipped Archive
.pkgMac OS X Installer Package
.rarWinRAR Compressed Archive
.sitStuffit Archive
.sitxStuffit X Archive
.tar.gzTarball File
.zipZipped File
.zipxExtended Zip File

Disk Image Files

.dmgMac OS X Disk Image
.isoDisc Image File
.toastToast Disc Image
.vcdVirtual CD

Developer Files

.cC/C++ Source Code File
.classJava Class File
.cppC++ Source Code File
.csVisual C# Source Code File
.dtdDocument Type Definition File
.javaJava Source Code File
.mObjective-C Implementation File
.plPerl Script

Backup Files

.bakBackup File
.ghoNorton Ghost Backup File
.oriOriginal File
.tmpTemporary File

Misc Files

.dbxOutlook Express E-mail Folder
.msiWindows Installer Package
.partPartially Downloaded File
.torrentBitTorrent File