| .a3m |
Authorware 3 Macintosh File |
| .a3w |
Authorware 3 Windows File |
| .a4m |
Authorware 4 Macintosh File |
| .a4w |
Authorware 4 Windows File |
| .atrac |
Sony ATRAC Audio File |
| .ark |
PowerDesk Pro Archive |
| .albm |
HP Photo Printing Software Album File |
| .artwork |
ArtStudio Image |
| .arl |
AOL Organizer File |
| .an2 |
Croc Legend of the Gobbos Animation File |
| .annot |
Adobe Digital Editions Annotations File |
| .alac |
ALAC Encoded Audio File |
| .af2 |
Micrografx ABC FlowCharter 2 File |
| .arpack |
ArtRage Package |
| .atahd |
ATA Hard Drive Flag File |
| .adox |
ActivDox Document |
| .agb |
Game Boy Advance ROM |
| .ava |
AvaaBook eBook |
| .adobebridge |
Adobe Bridge URL FIle |
| .a5rpt |
Alpha Five Project Report File |
| .arc.lh |
Nintendo Archive File |
| .avm |
Anime Music Video |
| .as2 |
ActivStudio Resource Pack |
| .azw3f |
Amazon eBook Metadata File |