| Extension | File Description |
| .SWQ | Uncommon Files |
| .SWR | Uncommon Files |
| .SWS | Uncommon Files |
| .SWS0 | Uncommon Files |
| .SWT | Video Files |
| .SWTH | Uncommon Files |
| .SWU | Uncommon Files |
| .SWV | Game Files |
| .SWW | Game Files |
| .SWX | Uncommon Files |
| .SWY | Uncommon Files |
| .SWZ | Web Files |
| .SX | Uncommon Files |
| .SX0 | Uncommon Files |
| .SX1 | Uncommon Files |
| .SX2 | Uncommon Files |
| .SX3 | Uncommon Files |
| .SX4 | Uncommon Files |
| .SX5 | Uncommon Files |
| .SX6 | Uncommon Files |
| .SX7 | Uncommon Files |
| .SX8 | Uncommon Files |
| .SX9 | Uncommon Files |
| .SXA | Uncommon Files |
| .SXB | Uncommon Files |
| .SXC | Spreadsheet Files |
| .SXD | GIS Files |
| .SXE | Uncommon Files |
| .SXF | Uncommon Files |
| .SXG | Text Files |
| .SXH | Uncommon Files |
| .SXI | Data Files |
| .SXJ | Uncommon Files |
| .SXK | Uncommon Files |
| .SXL | Uncommon Files |
| .SXLS | Uncommon Files |
| .SXLT | Uncommon Files |
| .SXM | Misc Files |
| .SXML | Uncommon Files |
| .SXN | Uncommon Files |
| .SXO | Uncommon Files |
| .SXP | Uncommon Files |
| .SXQ | Uncommon Files |
| .SXR | Uncommon Files |
| .SXS | Uncommon Files |
| .SXSCH | Uncommon Files |
| .SXT | Audio Files |
| .SXU | Uncommon Files |
| .SXV | Uncommon Files |
| .SXW | Text Files |
| .SXX | Uncommon Files |
| .SXY | Uncommon Files |
| .SXZ | Uncommon Files |
| .SY# | Uncommon Files |
| .SY0 | Uncommon Files |
| .SY1 | Uncommon Files |
| .SY2 | Uncommon Files |
| .SY3 | Data Files |
| .SY4 | Uncommon Files |
| .SY5 | Uncommon Files |
| .SY6 | Uncommon Files |
| .SY7 | Uncommon Files |
| .SY8 | Uncommon Files |
| .SY9 | Uncommon Files |
| .SYA | Uncommon Files |
| .SYB | Game Files |
| .SYC | Uncommon Files |
| .SYD | Uncommon Files |
| .SYE | Uncommon Files |
| .SYF | Uncommon Files |
| .SYG | Uncommon Files |
| .SYH | Uncommon Files |
| .SYI | Uncommon Files |
| .SYJ | Uncommon Files |
| .SYK | Uncommon Files |
| Extension | File Description |
| .SYL | Uncommon Files |
| .SYLK | Data Files |
| .SYM | Developer Files |
| .SYMBOLS | Uncommon Files |
| .SYN | Audio Files |
| .SYNC | Uncommon Files |
| .SYNCOPATIO | Uncommon Files |
| .SYNGUITAR | Uncommon Files |
| .SYNK5LICEN | Uncommon Files |
| .SYNKLICENS | Uncommon Files |
| .SYNTAX | Uncommon Files |
| .SYNTH | Uncommon Files |
| .SYNU | Uncommon Files |
| .SYO | Uncommon Files |
| .SYP | Uncommon Files |
| .SYQ | Uncommon Files |
| .SYR | Uncommon Files |
| .SYS | System Files |
| .SYS16 | Uncommon Files |
| .SYSBEEP2 | Uncommon Files |
| .SYSCMND | Uncommon Files |
| .SYSERRS | Uncommon Files |
| .SYSFOLDER | Uncommon Files |
| .SYSLOG | Uncommon Files |
| .SYSOP | Uncommon Files |
| .SYST2 | Uncommon Files |
| .SYSTEM | Game Files |
| .SYSTEMS | Uncommon Files |
| .SYSV | Uncommon Files |
| .SYT | Uncommon Files |
| .SYU | Uncommon Files |
| .SYV | Uncommon Files |
| .SYW | Audio Files |
| .SYX | Audio Files |
| .SYY | Uncommon Files |
| .SYZ | Uncommon Files |
| .SY_ | Compressed Files |
| .SY~ | Uncommon Files |
| .SZ | Settings Files |
| .SZ0 | Uncommon Files |
| .SZ1 | Uncommon Files |
| .SZ2 | Uncommon Files |
| .SZ3 | Uncommon Files |
| .SZ4 | Uncommon Files |
| .SZ5 | Uncommon Files |
| .SZ6 | Uncommon Files |
| .SZ7 | Uncommon Files |
| .SZ8 | Uncommon Files |
| .SZ9 | Uncommon Files |
| .SZA | Uncommon Files |
| .SZB | Uncommon Files |
| .SZC | Uncommon Files |
| .SZD | Uncommon Files |
| .SZE | Uncommon Files |
| .SZF | Uncommon Files |
| .SZG | Uncommon Files |
| .SZH | Uncommon Files |
| .SZI | Uncommon Files |
| .SZJ | Uncommon Files |
| .SZK | Uncommon Files |
| .SZL | Uncommon Files |
| .SZM | Uncommon Files |
| .SZN | Uncommon Files |
| .SZO | Uncommon Files |
| .SZP | Uncommon Files |
| .SZQ | Uncommon Files |
| .SZR | Uncommon Files |
| .SZS | Uncommon Files |
| .SZT | Uncommon Files |
| .SZU | Uncommon Files |
| .SZV | Uncommon Files |
| .SZW | Uncommon Files |
| .SZX | Uncommon Files |
| .SZY | Uncommon Files |
| .SZZ | Uncommon Files |
