| Extension | File Description |
| .SL9 | Uncommon Files |
| .SLA | Text Files |
| .SLABFACE | Uncommon Files |
| .SLAP | Uncommon Files |
| .SLASHER | Uncommon Files |
| .SLASHER2 | Uncommon Files |
| .SLB | Misc Files |
| .SLC | Uncommon Files |
| .SLD | Raster Image Files |
| .SLDASM | CAD Files |
| .SLDDRW | CAD Files |
| .SLDLFP | Uncommon Files |
| .SLDM | Data Files |
| .SLDPRT | CAD Files |
| .SLDX | Data Files |
| .SLE | Data Files |
| .SLEIGH | Uncommon Files |
| .SLF | Misc Files |
| .SLG | Uncommon Files |
| .SLH | Uncommon Files |
| .SLI | Uncommon Files |
| .SLICKEDIT | Uncommon Files |
| .SLIP | Uncommon Files |
| .SLJ | Uncommon Files |
| .SLK | Data Files |
| .SLL | Developer Files |
| .SLL1 | Uncommon Files |
| .SLL7 | Uncommon Files |
| .SLM | Uncommon Files |
| .SLN | Developer Files |
| .SLO | Uncommon Files |
| .SLOW | Uncommon Files |
| .SLP | Data Files |
| .SLQ | Uncommon Files |
| .SLR | Uncommon Files |
| .SLS | Uncommon Files |
| .SLST | Uncommon Files |
| .SLSTL | Uncommon Files |
| .SLT | Settings Files |
| .SLTNG | Uncommon Files |
| .SLU | Uncommon Files |
| .SLV | Uncommon Files |
| .SLW | Uncommon Files |
| .SLX | Uncommon Files |
| .SLY | Uncommon Files |
| .SLZ | Uncommon Files |
| .SM | Game Files |
| .SM$ | Uncommon Files |
| .SM+ | Uncommon Files |
| .SM0 | Uncommon Files |
| .SM1 | Uncommon Files |
| .SM2 | Uncommon Files |
| .SM3 | Uncommon Files |
| .SM4 | Uncommon Files |
| .SM5 | Uncommon Files |
| .SM6 | Uncommon Files |
| .SM7 | Uncommon Files |
| .SM8 | Uncommon Files |
| .SM9 | Uncommon Files |
| .SMA | Audio Files |
| .SMAF | Uncommon Files |
| .SMALL | Uncommon Files |
| .SMALLER | Uncommon Files |
| .SMART1 | Uncommon Files |
| .SMART2 | Uncommon Files |
| .SMART3 | Uncommon Files |
| .SMART4 | Uncommon Files |
| .SMARTDEBUG | Uncommon Files |
| .SMARTDTS | Uncommon Files |
| .SMARTGSOS | Uncommon Files |
| .SMARTHCGS | Uncommon Files |
| .SMARTMATH | Uncommon Files |
| .SMARTMISC | Uncommon Files |
| .SMARTPORT | Uncommon Files |
| .SMARTRECS | Uncommon Files |
| Extension | File Description |
| .SMARTSANE | Uncommon Files |
| .SMARTSPEEC | Uncommon Files |
| .SMARTSTACK | Uncommon Files |
| .SMB | Uncommon Files |
| .SMC | Game Files |
| .SMCL | Uncommon Files |
| .SMD | Game Files |
| .SMDF | Uncommon Files |
| .SMDL | Uncommon Files |
| .SME | Uncommon Files |
| .SMF | Audio Files |
| .SMFX | Uncommon Files |
| .SMG | Uncommon Files |
| .SMH | Uncommon Files |
| .SMHT | Uncommon Files |
| .SMI | Video Files |
| .SMIL | Video Files |
| .SMITH | Uncommon Files |
| .SMJ | Uncommon Files |
| .SMK | Video Files |
| .SML | Developer Files |
| .SML1 | Uncommon Files |
| .SML2 | Uncommon Files |
| .SML3 | Uncommon Files |
| .SMLICENSE | Uncommon Files |
| .SMM | Data Files |
| .SMN | Uncommon Files |
| .SMO | Uncommon Files |
| .SMOOTH | Uncommon Files |
| .SMOV | Uncommon Files |
| .SMP | GIS Files |
| .SMP3 | Uncommon Files |
| .SMPEG | Uncommon Files |
| .SMPG | Uncommon Files |
| .SMQ | Uncommon Files |
| .SMQ?? | Uncommon Files |
| .SMR | Uncommon Files |
| .SMRD | Misc Files |
| .SMS | Text Files |
| .SMT | Settings Files |
| .SMU | Uncommon Files |
| .SMV | Video Files |
| .SMW | Uncommon Files |
| .SMWT | Misc Files |
| .SMX | Uncommon Files |
| .SMY | Uncommon Files |
| .SMZ | Uncommon Files |
| .SMZIP | Game Files |
| .SM_ | Uncommon Files |
| .SN | Uncommon Files |
| .SN0 | Uncommon Files |
| .SN1 | Backup Files |
| .SN2 | Backup Files |
| .SN3 | Uncommon Files |
| .SN4 | Uncommon Files |
| .SN5 | Uncommon Files |
| .SN6 | Uncommon Files |
| .SN7 | Uncommon Files |
| .SN8 | Uncommon Files |
| .SN9 | Uncommon Files |
| .SNA | Backup Files |
| .SNAG | Data Files |
| .SNAKE | Uncommon Files |
| .SNAP | Uncommon Files |
| .SNAPFIREPR | Uncommon Files |
| .SNAPFIRESH | Data Files |
| .SNAPSHOT | Data Files |
| .SNARE2 | Uncommon Files |
| .SNB | Uncommon Files |
| .SNC | Uncommon Files |
| .SND | Audio Files |
| .SND2 | Uncommon Files |
| .SNDJ | Uncommon Files |
| .SNDR | Uncommon Files |
| .SNDS | Uncommon Files |
