Hi! You may remember me from Papa's Best STL Viewer ...

I've finished my Explorer extension that shows preview thumbnails for STL files. No need to open anything, all models display right in the file icon: https://papas-best.com/stlthumbnails_en

Of course it supports everything my viewer does (binary/ASCII STLs, colors, ...) and is just as fast.

Please let me know if it works for you!