| air | Adobe AIR Installation Package |
| aja | AJC Active Backup Archive |
| akt | AKT Compressed Archive |
| alz | ALZip Archive |
| ant | SPPAS Annotated Archive |
| ants | Tansee Message Transfer Backup |
| apk | Android Application Package |
| aplib | aPLib Compressed Data |
| appv | App-V Virtual Application Package |
| arc | LH ARC Compressed Archive |
| arc | FreeArc Archive File |
| arduboy | Arduboy Game Package |
| arj | ARJ Compressed Archive |
| ark | PowerDesk Pro Archive |
| asar | ASAR Archive |
| asdb | Asphyre Sphinx v2 Archive File |
| asec | Android Secure External Cache |
| ashbak | Ashampoo Backup Archive |
| asvf | Asphyre Sphinx v1 Archive File |
| ate | Microsoft Accounting Accountants Transfer |
| ati | Microsoft Accounting Import |
| avastsounds | Avast Antivirus Sound Package |
| awb | CRIWARE AWB Package |
| awi | AIM Widget Package |
| aza | ProSystem fx Engagement Admin Package |
| azp | ProSystem fx Engagement Binder Package |
| b1 | B1 Compressed Archive |
| b6z | B6Zip Archive |
| ba | Scifer External Header Archive |
| balz | BALZ Compressed Archive |
