Archival study materials for learning the Polish language.
Open-source torrent downloading client that you should use.
Despite the name, this Russian website is probably the best catalogue of torrents in any langauge on the internet. If you don't want to make an account, you can just search it on google using a search like site:rutracker.org mowimy po polsky
This is an autoamted indexer. Many torrents are low-quality or dead, but if it isn't on rutracker you might have to use it.
This is the largest archive of books on the internet, now at 65 million books. Since the domains get regularly pulled, access the linked wikipedia page to find the latest location.