| sm | SMath Studio Document |
| smdf | Surface Magic Design |
| smf | OpenOffice Math Formula |
| StarOffice StarMath Formula |
| smh | Sealed HTML Document |
| Sealed MHT Document |
| smht | Sealed MHT Document |
| smlx | Steel Markup Language Document |
| smm | Ami Pro Macro |
| smp | SLIM‐DataManager Workbook |
| smpl | Megahedron 3D Object |
| smst | Adobe Soundbooth Score Toolkit Document |
| smu | Simple MUsical Score Document |
| smus | Simple MUsical Score Document |
| smw | SLIM‐Metrics Workbook |
| smz | SMath Studio Compressed Document |
| snapdoc | Ashampoo Snap Document |
| sng | WorshipCenter Pro Song Data |
| snp | Microsoft Access Report SnapShot |
| snt | VX Show-n-Tell Slideshow |
| soap | Simple Object Access Protocol Message |
| sp | LTspice Netlist Data |
| spar | Spartan Document |
| spartan | Spartan Document |
| spc | LTspice Netlist Data |
| spd | Sealed PDF Document |
| SoftPlan Drawing Document |
| WinLens Lens Design |
| spdf | Sealed PDF Document |
| spect | Spectacles Document |
| spk | Bright Spark Document |
| spl | FutureSplash Animator Document |
| spn | Sealed PNG Image |
| spot | Sealed PowerPoint Template |
| spotm | Sealed PowerPoint 2007 Template without Macros |
| spotx | Sealed PowerPoint 2007 Template |
| spp | Sealed PowerPoint Presentation |
| sppt | Sealed PowerPoint Presentation |
| spptm | Sealed PowerPoint 2007 Presentation without Macros |
| spptx | Sealed PowerPoint 2007 Presentation |
| spr | Brother Powernote Spreadsheet |
| Psion Series 3 Spreadsheet |
| sprt | Sprintometer Document |
| sprz | Sprintometer Document |
| sps | Altova StyleVision SPS Document |
| spub | Swift Publisher Document |
| spw | SigmaPlot Worksheet |
| SLIM-MasterPlan Workbook |
| spx | Pfaff Stitch Creator Pattern |
| srb | Corel WordPerfect Scrap Book |
| srk | SharkCAD Drawing |
| srtf | Sealed Rich Text Format Document |
| sru | Search/Retrieve via URL Response Format Data |
| ssi | HTML Document with SSI |
| ssiw | Corel WordPerfect for Mac 4 Document |
| ssm | Samsung S Memo Data |
| ssn | Samsung S Note File |
| ssvg | Sealed SVG Document |
| ssw | Sealed SWF Document |
| sswf | Sealed SWF Document |
| st1 | DigiTitle Master Subtitle |
| stb | AutoCAD Named Plot Style Table |
| stc | OpenOffice Calc Template |
| std | Expressit SE CD/DVD Label Template |
| PROMT Translator Document |
| StarOffice Drawing Template |
| SureThing CD Labeler Document |
| step | Catia Document |
| ISO 10303 STEP Document |
| stepz | Catia Compressed STEP Document |
| sth | KG-Chart Design Data |
| sti | Sealed TIFF Image |
| StarOffice Impress Template |
| stif | Sealed TIFF Image |
| stk | Writer's Cafe StoryLines Document |
| stl | StereoLithography Data |
| stla | ASCII StereoLithography Data |
| stlb | StereoLithography Data |
| stml | Sealed HTML Document |
| story | Storyist Document |
