| Extension Name | Extension Type | Category | Dev.Company | File Format |
|---|---|---|---|---|
| .CH3 File Extension | Harvard Graphics DOS Chart File | Page Layout | Harvard Graphics | Binary |
| .HCX File Extension | ChartXL Chart | Data | Harvard Graphics | Unknown |
| .PRS File Extension | Harvard Graphics Presentation | Data | Harvard Graphics | Binary |
| .SY3 File Extension | Harvard Graphics Symbol File | Data | Harvard Graphics | Binary |
| .TP3 File Extension | Harvard Graphics DOS Template File | Page Layout | Harvard Graphics | Binary |