| som | Corel Quattro Pro Network Serial Number |
| songs | MediaShout Song Library |
| sopcinfo | SOPC Builder Information |
| sor | Adobe Flash Media Server Client Side Shared Object |
| sor | ChessDB Repertoire Data |
| sor | Corel Paradox Sort Definition |
| sor | OTDR Trace File |
| sos | Adventure SOS Compiled Walkthrough |
| sos | ANSYS EnSight Master Server Data |
| sos | Dynamite VSP Swept Object Style |
| sot | Adventure SOS Walkthrough Source |
| sot | CET Designer ProjectSymbols Standard Options Table |
| sot | Hollowcore Manufacturing System SOT Data |
| sou | WRAP Simulation Results Output Data |
| soundpack | SoundPackager Sound Package |
| soundscript | Rigs of Rods Sound Script Data |
| sov | 3DCS Advanced Analyzer/Optimizer SOVA Model |
| sox | BiRT Spreadsheet Report Executable File |
| sp | Micrografx ABC SnapGraphics Data |
| sp | SignPlot Document |
| sp | Simplexety Parameter File |
| sp | STK Sensor Pointing File |
| sp3 | NGS Standard Product 3 Format Data |
| spa | MikuMikuDance Sphere Mapping File |
| spa | Nicolet OMNIC Data |
| spa | Nintendo DS Particles Data |
| spa | Unreal Engine Spanish Language Data |
| spar | Simple Perl ARchive Manager Data |
| spb | SpareBrains Data |
| spb | ToolBook Instructor Assistant Book |
| spbm | VMware vSphere Storage Policy Based Management Data |
| spc | Crimson Editor Language Specification Data |
| spc | Galactic SPC Data |
| spc | Microsoft Software Publisher Certificate |
| spc | SNES Soundtrack Data |
