https://archive.org/search.php?query=subject%3A%22J.F.+Rutherford%22&and%5B%5D=mediatype%3A%22audio%22
And much more.
If, for instance, you wan to find out more about what is in the book “Studies in the Scriptures” and you would like to search it, here is a sample search using the word “Babylon”, https://archive.org/details/studies_in_the_scriptures_volume4/page/n193