| .ate |
Office Accounting Compressed Backup File |
| .ati |
Office Accounting Updated Company File |
| .avd |
Movie Edit Pro Video Information File |
| .avenirproj |
StoryMill Project |
| .actm |
AutoCAD Action Macro File |
| .ado |
Adobe Photoshop Duotone Options File |
| .amp |
Adobe Photoshop Curves Map File |
| .acbl |
Adobe Color Book Legacy File |
| .abdata |
Adobe Bridge Data File |
| .awt |
AbiWord Template |
| .ay |
AY Chiptune File |
| .aet |
After Effects Project Template |
| .am |
Automake Makefile Template |
| .acw |
Windows Accessibility Wizard File |
| .aria |
Chipsounds Sound File |
| .ave |
Avid User File |
| .afe |
Avid File Exchange File |
| .a52 |
Atari 5200 ROM |
| .adu |
Addict User Dictionary File |
| .asset |
Unity Asset File |
| .af3 |
Micrografx ABC FlowCharter 3/4 File |
| .a26 |
Atari 2600 ROM |
| .awp |
Ability Write Template |
| .aph |
Ability Album File |