| rcl | RockWorks Command Language Data |
| rcm | Autodesk Reality Captured Mesh |
| rcm | Logos Library System Data |
| rcn | QRacing Track Records Data |
| rco | PlayStation Portable Resource Data |
| rco | Source Insight Crash Recovery Data |
| rcq | RESTClient Requests File |
| rcr | SAP Business One XL Reporter Data |
| rcs | RCSWin Job Script |
| rctd | RabbitCT Dataset |
| rcut | Webinaria Recording Cut |
| rcv | Eudora Temporary Download Data |
| rcw | RaceSail Regatta Data File |
| rd | Reaction Data File |
| rd1 | DATAIR Retirement Plan Document System Data |
| rd3f | Ray Dream 3D Data |
| rd3x | Reflection Desktop Session Data |
| rd4a | Ray Dream 3D v4 Animation |
| rd5x | Reflection Desktop Session Data |
| rda | Oracle Database Storage Area |
| rda | Siemens MR Spectroscopy ASCII Data |
| rdat | RNA Data |
| rdb | Oracle Database Root |
| rdb | Redis Database |
| rdb | Retrospect Backup Set |
| rdb | Val Nav Database |
| rdbx | RiScan Pro Point Cloud Data |
| rdc | CYANA Residual Dipolar Coupling Restraint File |
| rdd | IBM Informix Genero Studio Data Schema |
| rdd | ReliaSoft ALTA RDD Data |
