| qcm | 3164 Emulator Quick Command |
| qcn | QPST Content |
| qcs | CADQC Standard Data |
| qct | Memory-Map Navigator QuickChart Data |
| qct | QuarkXPress Article Template |
| qct | Quick Chart Data |
| qd | Sharp MZ-series Emulator Quick Disk Data |
| qd0 | Omnis Quartz Segment 10 Data |
| qd1 | Omnis Quartz Segment 1 Data |
| qd2 | Omnis Quartz Segment 2 Data |
| qd3 | Omnis Quartz Segment 3 Data |
| qd4 | Omnis Quartz Segment 4 Data |
| qd5 | Omnis Quartz Segment 5 Data |
| qd6 | Omnis Quartz Segment 6 Data |
| qd7 | Omnis Quartz Segment 7 Data |
| 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 | Intuit 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 |
