| 2dr | Cadwork 2D Road Project |
| 3dp | Serif 3DPlus Project |
| 3dp | ArtCAM Pro Project |
| 3mx | 3Shape Convince Project Package |
| a2w | Alice v2 Project |
| a3p | Alice v3 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 |
| addoc | AudioDesk Project |
| adp | Microsoft Access Project |
| adpr | Atlantis Word Processor Project |
| adw | Asprova Project |
| aep | Adobe After Effects Project |
| aepx | Adobe After Effects XML Project |
| aesx | UBTECH Alpha 1 Pro Robot Project |
| aexml | STATISTICA Analysis Explorer Project |
| agif | Active GIF Creator Project |
| agk | App Game Kit Project |
| agp | ArtGem Project |
| agp | AppGini v2 Project |
| agr | Grace Project |
| am2 | AutoPlay Menu Studio 2.0 Project |
| am3 | AutoPlay Menu Studio 3.0 Project |
| am4 | AutoPlay Media Studio 4 Project |
| am6 | AutoPlay Media Studio 6 Project |
| amsproj | Ashampoo Music Studio Project |
| amw | Anark Media Workspace |
| an | Adobe Edge Animate Project |
| and | Apadana Project |
| anjuta | Anjuta DevStudio Project |
| ap12 | Siemens TIA v12 Project |
| ap13 | TIA Portal v13 Project |
