| smem | Samsung Smart Switch Message Data |
| smilebox | Smilebox Starter Archive |
| snap | Snappy Package |
| snappy | Snappy Compressed Data |
| snz | Snappy SNZ Compressed File |
| sof | ReSOF Compressed Archive |
| sp1 | ShadowProtect Spanned Backup |
| sp2 | ShadowProtect Spanned Backup |
| sp3 | ShadowProtect Spanned Backup |
| sp4 | ShadowProtect Spanned Backup |
| sp5 | ShadowProtect Spanned Backup |
| sparc | Skype Plugin Archive |
| spb | Samsung Kies Contacts Backup |
| spba | Samsung Kies Contacts Backup |
| spf | ShadowProtect Full Backup |
| spi | ShadowProtect Incremental Backup |
| spkz | Scribe Template Package |
| split | 3DBrowser Splitted File |
| sqx | SQX Compressed Archive |
| srep | SuperREP Compressed |
| srr | ReScene Data |
| ssb | Simply Safe Backup Archive |
| stix | StuffIt Expander Archive |
| sv4cpio | System V Release 4 CPIO Archive |
| sv4crc | System V Release 4 CPIO Checksum Data |
| swup | AC70 Software Update Package |
| szp | SecureZIP Archive |
| t4 | Top 4 Compressed Data |
| t7z | Littleutils To-7Zip Recompressed Archive |
| tar | Tape Archive |
| tardist | IRIX TAR Distribution Archive |
| targz | Unix Gzipped TAR Archive |
| taz | Unix Gzipped TAR Archive |
| tbk | The Bat! Backup Archive |
| tbz | Bzip Compressed Tape Archive |