STL stands for Standard Triangle Language and is a standard file format in 3D printing. STL files store information about 3D models by using geometry to represent the surface of the 3D model without any color or texture. Raise3D categorized STL files that are available for download into three separate categories. The first category focuses on 3D printed parts that can be produced by 3D printers from Raise3D. The second category focuses on COVID-19 related STL files. The final category discusses printer calibration.