Hi there,
Anskar from ca-ws wrote a script to create missing Index pages on
Wikisource for files that are in a Commons category. Here is the code:
https://ca.wikisource.org/wiki/Usuari:Anskarbot/Codis/Carrega_de_commons
If you have any question about it, he is in CC and his user page is:
https://ca.wikisource.org/wiki/Usuari_Discussi%C3%B3:Anskar
Cheers,
Micru