| dfti | FlexiWrite Document |
| dfx | Softdesk Drafix CAD Document |
| dg | Auto-trol Tech Illustrator Drawing |
| dg3 | DeltaGraph Document |
| dgk | Delcam 3D Model |
| dgm | Autodesk AutoCAD Civil 3D DGM Document |
| dgm | Lotus Freelance Graphics Diagram |
| dgn | Bentley MicroStation Drawing |
| dgpd | DeltaGraph Document |
| dgrh | DeltaGraph for Mac Document |
| dgs | Dagesh Pro Document |
| dhtml | Dynamic HTML Data |
| dhw | ACECAD DigiMemo Memo Document |
| dia | Dia Diagram |
| dif | Data Interchange Format |
| dio | Draw.io Diagram Document |
| dip | DipTrace PCB Document |
| diz | Archive Description |
| djc | RootPro CAD Document |
| dk | Danish Language Info File |
| dlst | DLsite Viewer Document |
| dma | IBM Rational DOORS Template |
| dmf | Delgine DeleD Model File |
| dmm | iMindQ 3.0 Mind Map Document |
| dmmt | iMindQ Mind Map Template |
| dmmw | iMindQ Mind Map Workbook |
| dmmx | iMindQ Mind Map Document |
| dmz | DMesh 3D Model |
| doc | Corel WordPerfect Document |
| doc | Microsoft Word Document |
| doc | WordStar 2000 Document |
| docb | XXE Docbook Document |
| doce | Document Manager Encrypted Word Document |
| dochtml | Microsoft Word HTML Document |
| docl | Document Manager Locked Word Document |
