Have you checked at Wayfair? Does your shade have the closed bottom like this one to indicate it is to hang over a table or is it open?

I did check. I can't find anything to indicate what fixture goes with it in the description. I have found the full pendant fixture (shade & fixture) for sale on other websites, but nothing that let me know what fixture alone I need to get in order to use the shade.

I have exactly that shade - with the glass diffuser for the bottom.

You might approach a lamp store (not a chain) and see if they could put one together using your shade. Some clever electrician might do it too.