| Extension | File Description |
| .ST3 | Uncommon Files |
| .ST4 | Uncommon Files |
| .ST5 | Uncommon Files |
| .ST6 | Uncommon Files |
| .ST7 | Uncommon Files |
| .ST8 | Uncommon Files |
| .ST9 | Uncommon Files |
| .STACK | Uncommon Files |
| .STAFF | Uncommon Files |
| .STAGE | Uncommon Files |
| .STAGE1 | Uncommon Files |
| .STAGE2 | Uncommon Files |
| .STAGE3 | Uncommon Files |
| .STAGE4 | Uncommon Files |
| .STAGE5 | Uncommon Files |
| .STAGE6 | Uncommon Files |
| .STAGE7 | Uncommon Files |
| .STAR | Uncommon Files |
| .STARPACK | Uncommon Files |
| .START | Uncommon Files |
| .STARTED | Uncommon Files |
| .STARTUP | Uncommon Files |
| .STAT | Uncommon Files |
| .STATE | Uncommon Files |
| .STATS | Uncommon Files |
| .STATUS | Uncommon Files |
| .STDCRC | Uncommon Files |
| .STDF | Uncommon Files |
| .STDFILE | Uncommon Files |
| .STDPRODOS | Uncommon Files |
| .STEALTH | Uncommon Files |
| .STEELDRUM | Uncommon Files |
| .STEGANO | Uncommon Files |
| .STEREO | Uncommon Files |
| .STH | Uncommon Files |
| .STIF | Uncommon Files |
| .STITCH | Uncommon Files |
| .STJ | Uncommon Files |
| .STKX | Uncommon Files |
| .STN | Uncommon Files |
| .STONE | Uncommon Files |
| .STORAGE | Uncommon Files |
| .STQ | Uncommon Files |
| .STQ?? | Uncommon Files |
| .STRANGE | Uncommon Files |
| .STRANGELOV | Uncommon Files |
| .STRAT | Uncommon Files |
| .STRING | Uncommon Files |
| .STRIPES | Uncommon Files |
| .STRIPES2 | Uncommon Files |
| .STRIPES3 | Uncommon Files |
| .STRUCT | Uncommon Files |
| .STS | Uncommon Files |
| .STSP | Uncommon Files |
| .STUDENT | Uncommon Files |
| .STUDIO | Uncommon Files |
| .STUFF | Uncommon Files |
| .STUPID | Uncommon Files |
| .STV | Uncommon Files |
| .STVINI | Uncommon Files |
| .STYXML | Uncommon Files |
| .STZ | Uncommon Files |
| .SU | Uncommon Files |
| .SU0 | Uncommon Files |
| .SU1 | Uncommon Files |
| .SU2 | Uncommon Files |
| .SU3 | Uncommon Files |
| .SU4 | Uncommon Files |
| .SU5 | Uncommon Files |
| .SU6 | Uncommon Files |
| .SU7 | Uncommon Files |
| .SU8 | Uncommon Files |
| .SU9 | Uncommon Files |
| .SUA | Uncommon Files |
| .SUBS | Uncommon Files |
| Extension | File Description |
| .SUBTITLE | Uncommon Files |
| .SUC | Uncommon Files |
| .SUCKS | Uncommon Files |
| .SUE | Uncommon Files |
| .SUG | Uncommon Files |
| .SUH | Uncommon Files |
| .SUITE | Uncommon Files |
| .SUJ | Uncommon Files |
| .SUK | Uncommon Files |
| .SUL | Uncommon Files |
| .SUMM | Uncommon Files |
| .SUMMARY | Uncommon Files |
| .SUMP | Uncommon Files |
| .SUMSHEET | Uncommon Files |
| .SUN3 | Uncommon Files |
| .SUN4 | Uncommon Files |
| .SUN5 | Uncommon Files |
| .SUPER | Uncommon Files |
| .SUPERCAT | Uncommon Files |
| .SUPERPRINT | Uncommon Files |
| .SUPPLEMENT | Uncommon Files |
| .SUPPORT | Uncommon Files |
| .SUQ | Uncommon Files |
| .SUQ?? | Uncommon Files |
| .SUR | Uncommon Files |
| .SURF | Uncommon Files |
| .SURFPLACE | Uncommon Files |
| .SUS | Uncommon Files |
| .SUSANNAH | Uncommon Files |
| .SUST | Uncommon Files |
| .SUT | Uncommon Files |
| .SUT?? | Uncommon Files |
| .SUU | Uncommon Files |
| .SUV | Uncommon Files |
| .SUW | Uncommon Files |
| .SUX | Uncommon Files |
| .SUY | Uncommon Files |
| .SUZ | Uncommon Files |
| .SV | Uncommon Files |
| .SV0 | Uncommon Files |
| .SV1 | Uncommon Files |
| .SV2 | Uncommon Files |
| .SV3 | Uncommon Files |
| .SV4 | Uncommon Files |
| .SV7 | Uncommon Files |
| .SV8 | Uncommon Files |
| .SV9 | Uncommon Files |
| .SVA | Uncommon Files |
| .SVB | Uncommon Files |
| .SVH | Uncommon Files |
| .SVJ | Uncommon Files |
| .SVK | Uncommon Files |
| .SVL | Uncommon Files |
| .SVM | Uncommon Files |
| .SVN | Uncommon Files |
| .SVO | Uncommon Files |
| .SVP | Uncommon Files |
| .SVQ | Uncommon Files |
| .SVQ?? | Uncommon Files |
| .SVR4B | Uncommon Files |
| .SVR4L | Uncommon Files |
| .SVT | Uncommon Files |
| .SVU | Uncommon Files |
| .SVUE | Uncommon Files |
| .SVV | Uncommon Files |
| .SVW | Uncommon Files |
| .SVY | Uncommon Files |
| .SVZ | Uncommon Files |
| .SW0 | Uncommon Files |
| .SW1 | Uncommon Files |
| .SW2 | Uncommon Files |
| .SW3 | Uncommon Files |
| .SW4 | Uncommon Files |
| .SW5 | Uncommon Files |
| .SW6 | Uncommon Files |
