| skel | Geomview OOGL Objects SKEL Data |
| skim | Skim Notes File |
| skindex | Apple Mail Index Data |
| skl | Autodesk Maya Skeleton Works Data |
| sklib | Skatter Library Data |
| skm | SSEYO Koan Data |
| skn | Windows Automotive Skin |
| skp | SSEYO Koan Play Data |
| skpkmz | SketchUp Data |
| skr | Gaussian Scratch File |
| skr | PGP Private Keyring File |
| skt | SSEYO Koan Design |
| skt | SSEYO Koan Play Data |
| sku | TomTom for R-Link Map Update |
| skypechatstyle | Skype Chat Style Data |
| skypeemoticonset | Skype Emoticon Pack |
| sl | RenderMan Shader Source |
| sl2 | Lowrance Sonar Log v2 File |
| sl3 | SQLite 3 Database |
| slb | Multiframe Sections Library |
| slb | PSpice Symbols Library |
| slc | SLiCe Format Data |
| sldasm | SolidWorks Assembly Document |
| sldblk | SolidWorks Blocks File |
| sldbombt | SolidWorks BOM Template |
| sldclr | SolidWorks Color Palette Data |
| sldd | Simulink Data Dictionary |
| slddc | Simulink Data Dictionary Cache |
| sldedb | SolidWorks Database |
| sldftp | SolidWorks Form Tool File |
| sldgtolfvt | SolidWorks Geometric Tolerance Style |
| sldholtbt | SolidWorks Hole Table Template |
| sldlfp | SolidWorks Library Features File |
| sldmat | SolidWorks Material Database |
| sldprt | SolidWorks Part Document |
