| qmsb | Questionmark Secure Data |
| qmt | Intuit Quicken v4 Memory List File |
| qmtf | Intuit Quicken Mac Transfer Format File |
| qmu | Quiver Mutation Data |
| qmv | Qvod Player Internal Data |
| qnf | Quad Design Netlist Format Data |
| qnt | Chromeleon Quantification Method |
| qnx | Intuit Quicken v4 Index File |
| qp | x265 Quantization Parameters Data |
| qp1 | QuickPAR Cache Data |
| qp2 | QuickPAR Cache Data |
| qpb | Intuit QuickBooks Point of Sale Data |
| qpd | Intuit QuickPay for Windows Data |
| qph | Intuit Quicken Price History |
| qph | Quicken Price History |
| qpl | KaleidaGraph Layout |
| qpst | Qualcomm QPST Data |
| qqe | Quick Quote Data |
| qr2 | Delphi Database Quick Report |
| qrd | BI/Query Result Set Data |
| qrf | QR Designer Form Data |
| qrl | QF-Test Run Log |
| qrm | Qworum Message |
| qro | MultiWell Quantized Rotation Data |
| qrq | Q&R Workstation Query Definition |
| qrr | BI/Query Result Set Informations |
| qrs | SlickRun MagicWord Pack |
| qrs | PhysioBank QRS Annotation File |
| qrt | QRT RayTracer Image |
| qrv | Tucnak QRV Data |
| qry | Microsoft Query File |
| qrz | QF-Test Compressed Run Log |
| qs | QSplat Model |
| qsc | KaleidaGraph Script |
| qsd | Quicken Data |