| qxf | QPS QINSy Chart Data |
| qxml | Question Master Administration Tool Data |
| qyb | Quantec Yardstick Bank Archive |
| qz | Create A Quiz Data File |
| qza | QIIME 2 Artifacts Data |
| qzb | QuaSZ Zbuffer Data |
| qzd | LS QuizPro Quiz Data |
| qze | LS QuizPro Quiz Data |
| qzp | QF-Test Zipped Split Run Log |
| qzs | LS QuizPro Quiz Data |
| r01 | MicroStation Modification System Resource File |
| r02 | MicroStation Modification System Resource File |
| r03 | MicroStation Modification System Resource File |
| r04 | MicroStation Modification System Resource File |
| r05 | MicroStation Modification System Resource File |
| r06 | MicroStation Modification System Resource File |
| r07 | MicroStation Modification System Resource File |
| r08 | MicroStation Modification System Resource File |
| r09 | MicroStation Modification System Resource File |
| r10 | MicroStation Modification System Resource File |
| r2k | Repertoire 2000 Music Database |
| r2lang | Rainlendar v2 Language Data |
| r2lic | Rainlendar v2 License Data |
| r2skin | Rainlendar Skin |
| r3f | SAP R/3 Form Data |
| r8 | Cubicomp PictureMaker Red Channel Image Data |
| r99 | MicroStation Modification System Resource File |
| raa | RiTE Ascii Animation |
| rab | Encyclopaedia Britannica 2002 Deluxe Data |
| rac | Racter Conversation Data |
| rac | Venue Race Application Race Data |
| rac | UltraEdit Autorecovery Data |
| rad | RFM Radiance Spectrum File |
| rag | RAM Advanse Data File |
| rai | SPEFO Stellar Spectra Analysis Data |