| qd8 | Omnis Quartz Segment 8 Data |
| qd9 | Omnis Quartz Segment 9 Data |
| qda | KaleidaGraph Data |
| qdat | QuickTime Install Cache |
| qdb | CUEcards Database |
| qdb | Quicken Data Backup |
| qdc | Quick Devis Database |
| qdd | Rimage QuickDisk Job Data |
| qdd | Snapform Designer Binary Data |
| qdes | DatabaseSpy Design Data |
| qdf | Quicken Data |
| qdf-backup | Intuit Quicken Data Backup |
| qdfm | Intuit Quicken for Mac Data File |
| qdfx | Intuit Quicken Financial Exchange File |
| qdi | Quanquest Data Mapping Data |
| qdi | Quicken Data Index |
| qdlx | Intuit Quicken for Mac QDLX Data |
| qdm | fsQCA Data |
| qdp | Quick and Dandy Plotter Data |
| qdt | Intuit Quicken v4 Data File |
| qdw | AnyQuest Questionnaire Definition Data |
| qef | Qubicle Exchange Data |
| qeff | QuickShow Effects Data |
| qel | Quicken Electronic Library |
| qem | ExpensAble Report |
| qep | IRMA 3270 Emulation Profile Data |
| qes | Epidata Dataform Definition |
| qex | ExpensAble Data |
| qext | Qlik Sense Extension |
| qf | Diploma Question File |
