| 2clk | Frontier for Mac Script |
| 3dfbat | 3DField Script |
| 3dmlw | 3D Markup Language for Web Document |
| 3xe | 3DLinX Entity Data |
| 4da | 4D User Forms Data |
| 4gl | IBM Informix 4GL Source Code |
| 4th | Forth Source Code |
| 4ui | ForeUI Plot |
| a1 | Free Pascal Compiled Archive |
| a3c | Alan v3 Adventure Code |
| a3l | Macromedia Authorware Library |
| a3m | Macromedia Authorware Macintosh File |
| a3w | Macromedia Authorware Windows File |
| a4e | Adobe Authorware External Library |
| a4l | Macromedia Authorware Library |
| a4m | Macromedia Authorware Macintosh File |
| a4p | Macromedia Authorware Source |
| a4w | Macromedia Authorware Windows File |
| a5l | Macromedia Authorware Library |
| a5m | Macromedia Authorware Macintosh File |
| a5p | Macromedia Authorware Source |
| a5rpt | Alpha Five Project Report |
| a5w | Alpha Five Web Publishing File |
| a5w | Macromedia Authorware Windows File |
| a5wcmp | Alpha Five Web Publishing Component |
| a6l | Macromedia Authorware Library |
| a6m | Macromedia Authorware Macintosh File |
| a6p | Macromedia Authorware Source |
| a6w | Macromedia Authorware Windows File |
| a7e | Macromedia Authorware Packaged Library |
| a7l | Macromedia Authorware Library |
| a7m | Macromedia Authorware Macintosh File |
| a7p | Macromedia Authorware Source |
| a7w | Macromedia Authorware Windows File |
| aah | Amazingly Abstracted HTML Document |
