Is there a place to see everyone that has a given theme

Try this:

Search on Google for the Theme Credits. I copied the first line of your footnotes. You need to find something in the theme that wont change. look for keywords, like the theme name. this is what i put in, without quotes:

“Powered by WordPress with Pool theme design by Borja Fernandez.”

Heres a link to my results:
https://www.google.com/search?hl=us&q=Powered+by+WordPress+with+Pool+theme+design+by+Borja+Fernandez.&btnG=Google-Suche&meta=

maybe you can apply this trick to other themes too. Most themes have a special footnote as credits to the author.
enjoy.

That is a great idea. You are very creative. thanks.