| aus | AutoREALM Symbols |
| auz | Ableton Live Authorization |
| ava | BrainVoyager QX ANCOVA Analysis Data |
| ava | Animation Master Model |
| ava3 | AVA CAD/CAM Data |
| avc | Kaspersky Anti-virus Database |
| avd | Avery LabelPro Database |
| avdl | Apache Avro IDL Data |
| avg | AVG Antivirus Virus Database |
| avn | altaVENTE Notes |
| avpr | Apache Avro Protocol Data |
| avro | Avro Serialized Data |
| avsc | Apache Avro Schema |
| avst | VirtualDub Template |
| avt | Marvelous Designer Avatar |
| avux | ARGUS Enterprise Exported Properties Data |
| avz | AviSys v6 Database Backup |
| aw | Answer Wizard Index |
| aw5 | MESA Actigraphy Actigraph Database |
| awd | AWARD BIOS Firmware Update |
| awe | Adobe Acrobat Bookmark XML Data |
| awh | ActiveWorlds Browser Help Data |
| awkw | Awkwords Generated Data |
| awn | Avant Window Navigator Theme Data |
| awr | Ad-Aware Reference Data |
| awr | Iconics AlarmWorX32 Report File |
| awsec | AirWatch Inbox Secure Content |
| awses | Active WebCam Session Data |
| awv | Iconics AlarmWorX32 Viewer File |
| axdt | ANSYS External Data |
| axe | Autoroute Export Data |
| axis | Microsoft SSAS AXIS Data |
| axm | AXMEDIS Object |
| axq | EditRocket Ada Editor Data |
| axs | AXIS Data File |
