hi! this is such a cute idea. and maybe you've abandoned this already, but the url-only search on gifcities should solve some of those mysteries, e.g
https://gifcities.org/special-search?q=dmobilean&flavor=lexical
https://gifcities.org/special-search?q=cwan&flavor=lexical
https://gifcities.org/special-search?q=fisan&flavor=lexical
etc :)
another thing that could be useful: you can use a file name used by gifcities (the long random code) to find every site that has used the same gif, by putting it in a url like this: 4VSJDP5RHA5J3WINKVI3QDEOFACGT4SB.gif —> https://gifcities.org/detail/4VSJDP5RHA5J3WINKVI3QDEOFACGT4SB