| rtdf | Rich Text Format Document |
| rte | Autodesk Revit Template |
| rtf | Rich Text Format Document |
| rtfd | Rich Text Format Document |
| TextEdit Document |
| rtg | Autodesk Maya 3D Scene Data |
| rtml | Runeberg Text Markup Language Document |
| rtt | RagTime Form |
| rtx | Rich Text Format Document |
| rt_ | Compressed RTF Document |
| rvd | VPHybridCAD Drawing |
| rvt | Autodesk Revit Document |
| rxf | Resort Chef Recipe Exchange Format Data |
| rxl | Seetrax XL Designer Document |
| s1a | Sealed PDF Document |
| s1e | Sealed Excel Worksheet |
| s1h | Sealed HTML Document |
| s1n | Sealed PNG Image |
| s1w | Sealed Word Document |
| s3d | Shape 3D v8 Document |
| s3dx | Shape 3D X Document |
| s3g | MakerBot S3G Document |
| s6bn | Microsoft Word 6 for Mac Template |
| s7 | Sibelius Music Notation |
| s8bn | Microsoft Word 98 for Mac Template |
| sadl | Semantic Application Design Language Document |
| saga | Gargoyle Saga Document |
| sagews | SageMath Sage Worksheet |
| sam | Ami Pro Document |
| saveddeck | Nokia Saved Web Page |
| sb1 | MemoryMixer Album |
| sbk | Scrapbook Factory Deluxe Scrapbook |
| sbml | Systems Biology Markup Language Document |
| sbp | Autodesk Sketchbook Express Image |
| sbpf | Small Business Publisher Document |
| sbsc | Adobe Soundbooth Score Document |
| sbst | Adobe Soundbooth Score Template |
| sc2 | Microsoft Schedule Plus Interchange |
| scc | StitchCraft Design |
| scd | Microsoft Schedule Plus Document |
| Scribus Compressed Document |
| scdoc | SpaceClaim Document |
| sch | EAGLE Schematic File |
| KiCad Schematic Document |
| Microsoft Schedule Plus File |
| schdot | Altium Designer Schematic Template |
| scld | ScoreCleaner Song |
| scm | Topanga SchematicMaker Document |
| scn | Caligari TrueSpace Scene |
| scne | Infini-D Scene |
| scriv | Scrivener Document |
| scrivx | Scrivener XML Document |
| scsv | Sealed CSV Document |
| scv | ScanVec CASmate Sign |
| scw | Movie Magic Screenwriter Document |
| Score Writer Document |
| SLIM‐Control Workbook |
| StitchCraft Design |
| scwx | Score Writer Document |
| scz | Wingz Script |
| sda | StarOffice Draw Template |
| sdb | OpenOffice Base Database |
| sdbn | Microsoft Word 4 for Mac Template |
| sdc | OpenOffice Calc Spreadsheet |
| sdd | StarOffice Presentation |
| sdf | Iconics GraphWorx32 Symbol Library |
| Sharpdesk Format Document |
| sdfa | Exocad 3D Model |
| sdk | Autodesk AutoSketch Drawing |
| sdl | Scene Description Language Document |
| Web Services Description Language Document |
| sdm | StarOffice Mail Document |
| sdn | Steel Detail Neutral File |
| sdnf | Steel Detail Neutral File |
| sdoc | Sealed Word Document |
| sdocm | Sealed Word 2007 Document without Macros |
| sdocx | Sealed Word 2007 Document |
| sdot | Sealed Word Template |
| sdotm | Sealed Word 2007 Template without Macros |
| sdotx | Sealed Word 2007 Template |
