I built this list with the Activity window from an old release of Safari. I expect there's lots of ways you could do it, I often contemplate such ways but this way works pretty well.
Just open the Activity window then visit a few random, at least somewhat sketchy websites. Pop-culture news sites are good. You'll see lots of 43 or 60 byte GIFs, commonly they will have lots of query parameters in the URLs, sometimes I see one-byte javascripts.
lots of websites pull shit from 20+ 3rd party domains.
An obnoxious number of sites block/don't render completely ( or at all ) without allowing shit from all over the web to load.
Just open the Activity window then visit a few random, at least somewhat sketchy websites. Pop-culture news sites are good. You'll see lots of 43 or 60 byte GIFs, commonly they will have lots of query parameters in the URLs, sometimes I see one-byte javascripts.