| 3dmk | 123D Make Project |
| 3dp | Serif 3DPlus Project |
| 3dp | ArtCAM Pro Project |
| 3mx | 3Shape Convince Project Package |
| a2w | Alice v2 Project |
| a3p | Alice v3 Project |
| abkprj | Ashampoo Backup Project |
| acd | Sony ACID Pro Project |
| acd-bak | Sony ACID Pro Project Backup |
| acid | Sony ACID Pro Project |
| actproj | Visual Studio .NET ACT Project |
| acz | AppCraft Project |
| adcp | Adobe Device Central Project |
| addoc | AudioDesk Project |
| adp | Microsoft Access Project |
| adw | Asprova Project |
| aep | Adobe After Effects Project |
| aepx | Adobe After Effects XML Project |
| aexml | STATISTICA Analysis Explorer Project |
| agif | Active GIF Creator Project |
| agp | ArtGem Project |
| agp | AppGini v2 Project |
| agr | Grace Project |
| aifb | AIF Builder Project |
| am2 | AutoPlay Menu Studio 2.0 Project |
| am3 | AutoPlay Menu Studio 3.0 Project |
| am4 | AutoPlay Media Studio 4 Project |
| am5 | AutoPlay Media Studio 5 Project |
| am6 | AutoPlay Media Studio 6 Project |
| am7 | AutoPlay Media Studio 7 Project |
