| .RAP | Open Source | File con layout di pagina | Raptor Flowchart File | RAPTOR | Open Source |
| .RB4 | Sarm Software | File con layout di pagina | Resume Builder 4 File | Sarm Resume Builder | Sarm Software |
| .RELS | Microsoft Corporation | File con layout di pagina | Open Office XML Relationships File | Microsoft Excel | Microsoft Corporation |
| .REZ | Monolith Productions | File con layout di pagina | Lithtech Game Engine Resource File | Dragon UnPACKer | Open Source |
| .RFD | Recogniform Technologies | File con layout di pagina | Recogniform Form Designer File | Recogniform | Recogniform Technologies |
| .RLF | ESRI | File con layout di pagina | ArcGIS Report Layout File | ESRI ArcGIS for Desktop | ESRI (Environmental Systems Research Institute) |
| .RMR | Individual Software Inc. | File con layout di pagina | ResumeMaker File | ResumeMaker | Individual Software Inc. |
| .ROW | Digital Rowing | File con layout di pagina | RowPro Rowfile | RowPro | Digital Rowing |
| .RPC | Synthrone | File con layout di pagina | Rich Page Content Document | Synthrone Crafter | Synthrone |
| .RPTR | Open Source | File con layout di pagina | RafflePrinter Document | RafflePrinter | Open Source |
| .RSM | RouterSim | File con layout di pagina | RouterSim Network Visualizer File | RouterSim CCNA Network Visualizer | RouterSim |
| .RWT | International Reading Association | File con layout di pagina | ReadWriteThink Timeline | International Reading Association RWT Timeline | International Reading Association |
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