| qbd | SQL Navigator Query Builder Data |
| qbi | Intuit QuickBooks Image file |
| qbk | Intuit QuickTax 2009 Backup |
| qbl | Intuit QuickBooks License File |
| qbmb | QuickBooks Backup |
| qbmd | QuickBooks Backup |
| qbo | Intuit QuickBooks Online Bank Statement |
| qbp | Intuit QuickBooks Print File |
| qbquery | MySQL Query Browser Saved SQL Query |
| qbt | Intuit QuickBooks Temporary File |
| qbz | Quick Trial Balance Data File |
| qcc | QC-Calc Data Collection |
| qch | Intuit Quicken for DOS Data File |
| qch | QT Compressed Help |
| qci | Cliq Accessories Phonebook Index |
| qcl | Quark Color Library |
| qcm | 3164 Emulator Quick Command |
| qcn | QPST Content |
| qct | Quick Chart Data |
| qd0 | Omnis Quartz Segment 10 Data |
| qd8 | Omnis Quartz Segment 8 Data |
| qda | KaleidaGraph Data |
| qdat | QuickTime Install Cache |
| qdb | Quicken Data Backup |
| qdd | Rimage QuickDisk Job Data |
| qdes | DatabaseSpy Design Data |
| qdf | Quicken Data |
| qdfm | Quicken Data File (Macintosh) |
| qdfm | Intuit Quicken for Mac Data File |
| qdfx | Intuit Quicken Financial Exchange File |
