| 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 |
| qsc | KaleidaGraph Script |
| qsd | Quicken Data |
| qsf | Quintessential Player Family Skin |
| qsf | Qualtrics Survey Data |
| qsi | QTL Simulation Information File |
| qsk | Quintessential Player Kid Skin |
| qsr | CARE-S Water Quality Simulation Results Data |
| qst | KaleidaGraph Style |
| qst | Intuit Quicken v4 Data File |
| qstx | Quest III Quote File |
| qt3d | QT 3D Data |
| qtb | ExamView Question Bank Data |
| qtch | QuickTime Player Cache |
| qtf | Qtracker Filter |
| qtg | QTgrader Data |
| qth | WinOrbit Observer Database |
| qtindex | Adobe Premiere QuickTime Index |
| qtr | Vectorworks v11 Workspace |
| qtx | QuaSZ Texture |
| qtx | QuickTime Extension |
| qual | Quality Score File |
| que | CuteFTP Queue Data |
| query | Microsoft PCHealth Query File |
| quiz | Question Object File Format |
| quox | Question Object File Format |
| qut | IBM Voice Type Language Vocabels Data |
