| .ais |
ACDSee Image Sequence File |
| .a5l |
Authorware 5 Library |
| .a65 |
Authorware 6.5 File |
| .asat |
Assemble SAT 3D Model File |
| .av |
Video Surveillance File |
| .atr |
Atari Disk Image |
| .aic |
Advanced Image Coding File |
| .acx |
Atari ST Program |
| .acrodata |
Acrobat Data File |
| .a00 |
ALZip Second Split Archive File |
| .a01 |
ALZip Third Split Archive File |
| .a02 |
ALZip Fourth Split Archive File |
| .an1 |
Street Atlas USA Draw File |
| .awb |
Adaptive Multi-Rate Wideband (AMR-WB) File or Video Games Archive Format |
| .aca |
Agent Character Animation File |
| .agd |
AgileGraph Data File |
| .asws |
Avast! Skin File |
| .aswcs |
Avast! Compressed Skin File |
| .aos |
ARCHOS PCtablet Firmware File |
| .apm |
Aldus Placeable Metafile Image |
| .ab2 |
Print Shop Address Book File |
| .as4 |
askSam Backup File |
| .arh |
ProTool Compressed Project File |
| .afs |
STAAD.foundation Project File |