| shd | Windows Shadow Header |
| she | Medusa CAD Sheet Data |
| sheet | Dia Sheet Data |
| shelx | SHELX Data |
| shf | PGP Share Data |
| shft | Shift Work Calendar Data File |
| shh | Adobe Photoshop Shadow and Highlight Data |
| shl | Inno Setup String Tables File |
| shlibs | Debian Package Shared Library Information |
| shm | Siebel Server Shared Memory File |
| sho | Show Pro Software Show Document |
| shu | SnippetHub Export |
| si2 | SAS Index |
| si3 | ChessDB Index Data |
| si4 | Scid Database Index |
| si7 | SAS Index |
| siard | SIARD Database Archive |
| sic | Intuit Quicken Order Data |
| sic | Sick Submitter Data File |
| sid | Steam Game Backup Data |
| sidb | iTunes Authorization Data File |
| sidd | iTunes Authorization Data File |
| sidn | iTunes Authorization Data File |
| sie | SIE Data |
| sif | Cytoscape Simple Interaction Format File |
| sif | ElmerSolver Command File |
| sif | KilnView Log Signature |
| siff | Scene Interchange File Format Data |
| sig | Crestron Test Manager Signal Data |
| sig | Powersim Studio Simulation Game |
| sign | GNU Privacy Guard Signature Data |
| silo | MeshTV Data |
| sim | CARE-S InfoWorks Simulation Parameters Data |
| sim | Simile Model |
| sim | Steam Game Backup Metadata |