| shp | CARE-S InfoWorks Pipe Cross-section Data |
| shphst | OnScale Shape History Data |
| shsh2 | iOS SHSH Blob |
| sht | WaveStar Datasheet |
| shu | SnippetHub Export |
| shx | Autodesk AutoCAD Compiled Shapefile |
| si2 | SAS Index |
| si3 | ChessDB Index Data |
| si4 | Scid Database Index |
| si7 | SAS Index |
| sia | SIA Metadata |
| sia | Spin It Again Track Data |
| siard | SIARD Database Archive |
| sic | Intuit Quicken Order Data |
| sic | Sick Submitter Data File |
| sid | Microsoft SMS Software Inventory Data |
| sid | Steam Game Backup Data |
| sidb | iTunes Authorization Data File |
| sidd | iTunes Authorization Data File |
| sidn | iTunes Authorization Data File |
| sie | SIE Data |
| sif | Andor SIF 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 | Microsoft OneNote Signature Data |
| sig | Powersim Studio Simulation Game |
| sign | GNU Privacy Guard Signature Data |
| signature | e-Filing Signature Data |
| signed | BlackBerry 10 App Certificate |
| sik | Microsoft Word Backup Data |
| silk | Symbolic Link Spreadsheet |
| silo | MeshTV Data |
