Dozens of different ART formats exists, but quiet a few are either vectors or even 3D models, which are probably the ones that can be prepared or directly exported to STL format and suitable for art to stl conversion.
What is often done is that vector files are used to build meshes that are then exported to STL format for 3D printing, but that is rarely direct conversion and usually requires a lot of work.
Updated: September 22, 2023