| spq | SPSS Saved ODBC Query |
| spr | ArchiCAD Slab Properties |
| sprf | Manip Saved Proof File |
| sps | SPSS Syntax File |
| spub | BeLight Disc Cover Data |
| spud | iGO Primo SpeedCam Database Update |
| spv | SPSS Output Document |
| spvchain | MultiBit Locally Stored Blockchain |
| sq3 | SQLite 3 Database |
| sq7 | Daktronics Venus 7000 Sequence Data |
| sqb | SQL Backup SQL Server Backup |
| sqd | Sysquake SQ Data |
| sqd | FidoNet Squish Data |
| sqg | SeQuence Graph Data |
| sqi | FidoNet Squish Index Data |
| sql | FidoNet Squish Lastread Storage |
| sql | SQL Script |
| sqlite | SQLite Database |
| sqlite2 | SQLite 2.0 Database |
| sqlite3 | SQLite 3 Database |
| sqlitedb | SQLite Database |
| sqlt | SQLite Database |
| sqm | Microsoft Message Queuing Data |
| sqp | Sonique Audio Search Query Result Data |
| sqs | SQL Script Sequences |
| squ | LabWindows Test Sequence |
| sqv | VisionWorks LS Image Sequence Data |
| sqy | Xaira Saved Query |
| sr1 | SIR Schema Rectype and Variable Specs Data |
| sr2 | SIR Schema Textual Specs Data |
| sr3 | SIR Index and Data |
| sr4 | SIR Procedure Definitions Data |
| sr5 | SIR Database Journal Data |
| sr6 | SIR Alternate Index |
| sr7 | SAS Item Storage |