| ssn | Railway Operation Simulator Session Data |
| sso_pt | Foxit Reader Data |
| ssr | FLEXIT Singleshot Survey Raw Data |
| sss | Stardock WindowsBlinds Substyles |
| sst | Microsoft Serialized Certificate Store |
| ssw | Sony-Ericsson Firmware |
| ssy | ScreenShare Compressed Data |
| ssz | Spider Player Skin |
| st0 | HSPICE Simulation Summary Data |
| st0 | SPICE Status Data |
| st2 | SAS Audit Data |
| st7 | SAS Audit Data |
| sta | Adobe Photoshop CS Color Statistics |
| sta | STATISTICA Spreadsheet File |
| stak | HyperCard Stack Data |
| stan | Stan Model File |
| startupinfo | E-Prime StartupInfo File |
| stat | EnergyPlus Weather Data Summary Report |
| stat | SAM Training Statistics Data |
| state | Windows Photo Gallery State File |
| states | IconX Preset Data |
| stats | FreeSurfer Statistics File |
| stbom | Catia SmartBOM Data |
| stc | BrainVoyager QX Slice Time Course Data |
| stdf | SEDana Standard Test Data Format Data |
| stdid | RSA Soft Token Seed |
| stdl | Swift To-Do List Database |
| stdsrcmdl | Softimage Standard Source Model |
| steamstart | Valve Steam Start |
| stencyl | Stencyl Game Data |
