There used to be the SolidWorks Manufacturing Partner program, making it easy to find manufacturing vendors who used SolidWorks, but that quietly went away some time ago. Is there something comparable to that today?
Depending on the type of supplier 3dcontent central is a good place to look they all wont be there but there are bunches.
There is a list of many of the people that have passed their CSWP tests. It is available by clicking the "certifications" portion of the customer portal. Admittedly, it is far from being a complete list of all SW users but it can be sorted in various fields (location, name, etc) and may be a little bit helpful.
Here's a short list
Here's another list:
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