| apln | Adobe InDesign Plug-in |
| aplp | Audials One Plug-in Package |
| appdownload | AppStore Partially Downloaded App |
| appex | Mac OS X Application Extension |
| appimage | AppImage Image |
| aqq | AQQ Plug-in |
| aria2 | aria2 Control Data |
| artask | BMC Remedy User Tool Shortcut |
| asd | Lotus 1-2-3 Screen Driver |
| asl | Adobe Photoshop Layer Style |
| assistant | HP Printer Utility for Mac Assistant Plugin |
| ast | ASTree Program |
| asv | Adobe Photoshop Selective Color |
| atahd | Puppy Linux ATA Hard Drive Flag |
| atf | Adobe Photoshop Transfer Functions |
| automaticdestinations-ms | Windows Jump List |
| ava | Adobe Photoshop Variations File |
| avastvpn | Avast SecureLine VPN License Data |
| avh | Pioneer AVH Firmware Update |
| awc | Emulex AWC Firmware Update |
| axx | AxCrypt Encrypted File |
| backup | Backup Copy File |
| bai | BUILD2WIN Add-in |
| bak | Backup Copy File |
| bcf | MapTek Vulcan Script |
| bcs | Sonic Foundry Batch Converter Script |
| bdd | BRender Device Driver |
| bea | BEA WebLogic Platform License |
| beb | EEC Analyzer Data |
| bem | Babel Enterprise Module |
