| .#ib | Printer data file (LocoScript) |
| .#sc | Printer data file (LocoScript) |
| .#st | Standard mode printer definitions (LocoScript) |
| .$$$ | Temporary file |
| .$00 | Pipe file (DOS) |
| .$db | Temporary file (dBASE IV) |
| .$ed | Editor temporary file (MS C) |
| .$o1 | Pipe file (DOS) |
| .$vm | Virtual manager temporary file (Windows 3.x) |
| .000 | Compressed harddisk data (DoubleSpace) |
| .001 | Fax (many) |
| .075 | 75x75 dpi display font (Ventura Publisher) |
| .085 | 85x85 dpi display font (Ventura Publisher) |
| .091 | 91x91 dpi display font (Ventura Publisher) |
| .096 | 96x96 dpi display font (Ventura Publisher) |
| .0b | Printer font with lineDraw extended character set (PageMaker) |
| .1 | Roff/nroff/troff/groff source for manual page (cawf2.zip) |
| .15u | Printer font with PI font set (PageMaker) |
| .1st | Usually README.1ST text |
| .301 | Fax (Super FAX 2000 - Fax-Mail 96)) |
| .386 | Intel 80386 processor driver (Windows 3.x) |
| .3ds | Graphics (3D Studio) |
| .3fx | Effect (CorelChart) |
| .3gr | Data file (Windows Video Grabber) |
| .3t4 | Binary file converter to ASCII (Util3) |
| .4c$ | Datafile (4Cast/2) |
| .4sw | 4dos Swap File |
| .4th | Forth source code file (ForthCMP - LMI Forth) |
| .669 | Music (8 channels) (The 669 Composer) |
| .6cm | Music (6 Channel Module) (Triton FastTracker) |
| .8 | A86 assembler source code file |
| .8cm | Music (8 Channel Module) (Triton FastTracker) |
| .8m | Printer font with Math 8 extended character set (PageMaker) |
| .8u | Printer font with Roman 8 extended character set (PageMaker) |
| .a | Ada source code file |
| .a | Library (unix) |
| .a11 | Graphics AIIM image file |
| .ab6 | Datafile (ABStat) |
| .ab8 | Datafile (ABStat) |
| .abk | Automatic backup file (CorelDRAW) |
| .abs | Abstracts (info file) |
| .abs | Data file (Abscissa) |
| .aca | Project (Project Manager Workbench) |
| .acb | Graphics (ACMB) |
| .acc | Program (DR-DOS - ViewMax) (GEM / resident) |
| .act | Actor source code file |
| .act | Foxdoc Action Diagrams (FoxPro) |
| .act | Presentation (Action!) |
| .ad | Screen saver data (AfterDark) |
| .ada | Ada source code file |
| .adb | Ada Package Body |
| .adc | Bitmap graphics (16 colors) (Scanstudio) |
| .adi | Graphics (AutoCAD) |
| .adl | Mca adapter description library (QEMM) |
| .adn | Add-in (Lotus 1-2-3) |
| .ads | Ada Package Specification |
| .adt | Datafile for cardfile application (HP NewWave) |
| .adt | Fax (AdTech) |
| .adx | Document (Archetype Designer) |
| .af2 | Flowchart (ABC FlowCharter 2.0) |
| .afi | Truevision bitmap graphics |
| .afl | Font file (for Allways) (Lotus 1-2-3) |
| .afm | Type 1 font metric ASCII data for font installer (ATM - many) |
| .afm | Datafile for cardfile application (HP NewWave) |
| .ai | Vector graphics (Adobe Illustrator) |
| .aif | AIFF audio |
| .aiff | AIFF audio |
| .ain | Compressed file archive created by AIN |
| .aio | APL file transfer format file |
| .ais | Array of Intensity Samples graphics (Xerox) |
| .aix | Datafile for cardfile application (HP NewWave) |
| .all | Format file for working pages (Always) |
| .all | General printer information (WordPerfect for Win) |
| .all | Symbol and font files (Arts & Letters) |
| .alt | Menu file (WordPerfect Library) |
| .amf | Music (Advanced Module Format) |
| .amg | Compressed file archive created by AMGC |
| .amg | System image file (Actor) |
| .ani | Animation (Presidio - many) |
| .anm | Animation (Deluxe Paint Animator) |
| .ann | Help Annotations (Windows 3.x) |
| .ans | Ansi graphics (character animation) |
| .ans | Ascii text ANSI character set (NewWave Write) |
| .aos | Add-On Software (Nokia 9000) |
| .ap | Compressed Amiga file archive created by WHAP |
| .ap | Datafile (Datalex EntryPoint 90) |
| .apc | Printer driver (Lotus 1-2-3) |
| .apd | Printer driver (Lotus 1-2-3) |
| .apf | Printer driver (Lotus 1-2-3) |
| .api | Passed parameter file (1st Reader) |
| .api | Printer driver (Lotus 1-2-3) |
| .apl | APL work space format file |
| .app | Add-in application file (Symphony) |
| .app | Application object file (dBASE Application Generator) |
| .app | Executable application file (DR-DOS - NeXTstep - Atari) |
| .app | Generated application (FoxPro) |
| .apr | Employee performance review (Employee Appraiser) |
| .apx | Appexpert database file (Borland C++ 4.5) |
| .arc | Compressed file archive created by ARC (arc602.exe/pk361.exe) |
| .arc | Compressed file archive created by SQUASH (squash.arc) |
| .arf | Automatic Response File |
| .ari | Compressed file archive created by ARI |
| .arj | Compressed file archive created by ARJ (arj241.exe) |
| .ark | Arc file archive created by CP/M port of ARC file archiver |
| .ark | Compressed file archive created by QUARK |
| .arr | Arrangement (Atari Cubase) |
| .art | Graphics (scrapbook) (Art Import) |
| .art | Raster graphics (First Publisher) |
| .arx | Compressed file archive created by ARX |
| .asc | Ascii text file |
| .asc | Transport armor file (PGP) |
| .asd | Autosave file (Word for Windows) |
| .asd | Presentation (Astound) |
| .asd | Screen driver (Lotus 1-2-3) |
| .asf | Datafile (STATGRAPHICS) |
| .asf | Screen font (Lotus 1-2-3) |
| .ash | Assembly language header file (TASM 3.0) |
| .asi | Assembler include file (Turbo C - Borland C++) |
| .asm | Assembly source code file |
| .aso | Assembler object (object orientated) file (Turbo Assembler) |
| .asp | Aspect source code file (Procomm Plus) |
| .asp | Association of Shareware Professionals OMBUDSMN.ASP notice |
| .at2 | Auto template (Aldus Persuasion 2.0) |
| .atm | Adobe Type Manager data/info |
| .au | Sound (ULAW audio) file (SUN Microsystems) |
| .aux | Auxillary references (TeX/LaTeX) |
| .aux | Auxiliary dictionary (ChiWriter) |
| .ava | Publication (Avagio) |
| .avi | Audio Video Interleaved animation file (Video for Windows) |
| .avs | Image - AVS X image file |
| .aw | Text file (HP AdvanceWrite) |
| .awk | Awk script/program |
| .awm | Movie (Animation Works) |
| .aws | Data (STATGRAPHICS) |
| .b | Batch list (APPLAUSE) |
| .b&w | Black and white graphics (atari - mac) |
| .b&w | Mono binary screen image (1st Reader) |
| .b1n | Both mono and color binary screen image (1st Reader) |
| .b30 | Printer font (JLaser - Cordata) (Ventura Publisher) |
| .b8 | Raw graphics (one byte per pixel) plane two (PicLab) |
| .b_w | Black and white graphics (atari - mac) |
| .bad | Bad file (Oracle) |
| .bak | Backup file |
| .bal | Music score (Ballade) |
| .bar | Horizontal bar menu object file (dBASE Application Generator) |
| .bas | Basic source code file |
| .bat | Batch file (DOS) |
| .bb | Database backup (Papyrus) |
| .bbl | Bibliographic reference (TeX/BibTeX) |
| .bbm | Brush (Deluxe Paint) |
| .bbs | Bulletin Board System announce or text info file |
| .bch | Batch process object file (dBASE Application Generator) |
| .bch | Datafile (Datalex EntryPoint 90) |
| .bco | Outline font description (Bitstream) |
| .bcp | Borland C++ makefile |
| .bcw | Environment settings (Borland C++ 4.5) |
| .bdf | Bitmap Distribution Format font file (X11) |
| .bdf | Datafile (Egret) |
| .bdr | Border (MS Publisher) |
| .bez | Outline font description (Bitstream) |
| .bf2 | Bradford 2 font |
| .bfm | Font metrics (unix/Frame) |
| .bfx | Fax (BitFax) |
| .bga | Bitmap graphics |
| .bgi | Borland Graphics Interface device driver |
| .bib | Bibliography (ASCII) |
| .bib | Database - not compatible with TeX format (Papyrus) |
| .bib | Literature database (TeX/BibTeX) |
| .bif | Binary Image Format b&w graphics (Image Capture board) |
| .bin | Binary file |
| .bio | OS/2 BIOS |
| .bit | Bitmap X11 |
| .bk | Faxbook (JetFax) |
| .bk! | Document backup (WordPerfect for Win) |
| .bk1 | Timed backup file for document window 1 (WordPerfect for Win) |
| .bk2 | Timed backup file for document window 2 (WordPerfect for Win) |
| .bk3 | Timed backup file for document window 3 (WordPerfect for Win) |
| .bk4 | Timed backup file for document window 4 (WordPerfect for Win) |
| .bk5 | Timed backup file for document window 5 (WordPerfect for Win) |
| .bk6 | Timed backup file for document window 6 (WordPerfect for Win) |
| .bk7 | Timed backup file for document window 7 (WordPerfect for Win) |
| .bk8 | Timed backup file for document window 8 (WordPerfect for Win) |
| .bk9 | Timed backup file for document window 9 (WordPerfect for Win) |
| .bkp | Backup file (Write - TurboVidion DialogDesigner) |
| .bkw | Mirror image of font set (FontEdit) |
| .bld | Bloadable picture (BASIC) |
| .blk | Temporary file (WordPerfect for Win) |
| .bm | Bitmap graphics |
| .bmk | Help Bookmarks (Windows 3.x) |
| .bmp | Image - Bitmap graphics (PC Paintbrush - many) |
| .bmp24 | Image - Microsoft Windows 24-bit bitmap image file |
| .bnk | Adlib instrument bank file |
| .boo | Compressed file ASCII archive created by BOO (msbooasm.arc) |
| .bpc | Chart (Business Plan Toolkit) |
| .bpt | Bitmap fills file (CorelDRAW) |
| .br | Script (Bridge) |
| .brd | Eagle Layout File |
| .brk | Fax (Brooktrout Fax-Mail) |
| .bsa | Compressed file archive created by BSARC |
| .bsc | Compressed Apple II file archive created by BINSCII |
| .bsc | Database (Source Browser) |
| .bsc | Pwbrmake object file (MS Fortran) |
| .btm | Batch To Memory batch file (4DOS) |
| .bug | Bugs and Problems |
| .bup | Backup file |
| .but | Button definitions (Buttons!) |
| .buy | Datafile format (movie) |
| .bv1 | Overflow file below insert point in Doc 1 (WordPerfect for Win) |
| .bv2 | Overflow file below insert point in Doc 2 (WordPerfect for Win) |
| .bv3 | Overflow file below insert point in Doc 3 (WordPerfect for Win) |
| .bv4 | Overflow file below insert point in Doc 4 (WordPerfect for Win) |
| .bv5 | Overflow file below insert point in Doc 5 (WordPerfect for Win) |
| .bv6 | Overflow file below insert point in Doc 6 (WordPerfect for Win) |
| .bv7 | Overflow file below insert point in Doc 7 (WordPerfect for Win) |
| .bv8 | Overflow file below insert point in Doc 8 (WordPerfect for Win) |
| .bv9 | Overflow file below insert point in Doc 9 (WordPerfect for Win) |
| .bwb | Spreadsheet application (Visual Baler) |
| .bwr | Beware (buglist) (Kermit) |
