| sdltb | SDL MultiTerm Termbase |
| sdltm | SDL Trados Translation Memory |
| sdlxliff | SDL Trados XLIFF Localization |
| sdm | STATISTICA Workspace |
| sdm | BrainVoyager QX Design Matrix |
| sdmx | Statistical Data and Metadata eXchange Dataset |
| sdo | DB/TextWorks Database Deferred Update Directory |
| sdpa | SDPA Data |
| sdpc | CoCreate SolidDesigner Data |
| sdtbx | XTRF Terminology Database |
| sdtheme | Nintendo Desktop Manager Theme Data |
| sdtid | RSA SecurID Software Token Import Data |
| sdts | Spatial Data Transfer Standard File |
| sdv | WDK Static Driver Verifier Rules |
| sdxf | Structured Data eXchange Format Data |
| sdxm | SDX Signed Data |
| sdxx | Autodesk AutoCAD Civil 3D Survey Database Extended Properties |
| sdy | Starmoney Database File |
| se1 | AD Summation iBlaze Database |
| sea | MAXQDA Saved Search |
| searchconnector-ms | Windows Search Connector Data |
| seawifs | SeaWiFS Data |
| sec | Concordance User Management Control Data |
| sec | PTC Creo Section Data |
| sec | Migration Wizard Secondary IFF File |
| seco | MSX Configurator Software Update |
| secstore | Adobe Acrobat Security Store File |
| sedr | URAP Supplemental Experiment Data Record |
| see | LISCAD Database |
| seek | Word List Expert Seek List Data |