| .amb |
All My Books Database File |
| .acg |
Audio Comparer Group File |
| .avchd |
High Definition Video File |
| .asvf |
Asphyre Sphinx Archive File |
| .aplibrary |
Aperture Library |
| .a2i |
Adlib Tracker II Instrument File |
| .a2b |
Adlib Tracker II Instrument Bank |
| .asv |
Finale Auto-save File |
| .asvx |
Finale Auto-save File |
| .asef |
GrabCAD 3D CAD model file |
| .anh |
Project ROME File |
| .archiver |
Archiver Compressed File Archive |
| .age3xsav |
Age of Empires 3: The WarChiefs Save File |
| .age3ysav |
Age of Empires 3: The Asian Dynasties Save File |
| .age3rec |
Age of Empires 3 Recording |
| .age3xrec |
Age of Empires 3: The WarChiefs Recording |
| .age3yrec |
Age of Empires 3: The Asian Dynasties Recording |
| .acz |
AppCraft Project |
| .a7p |
Authorware 7 Project |
| .a7r |
Authorware 7 Runtime File |
| .ang |
Anghami Audio File |
| .afdesign |
Affinity Design Document |
| .acww |
Animal Crossing Wild World Pattern File |
| .aria2 |
aria2 Control File |