Go over to the Internet Archive site. Type various key words into the search engine, words such as "witchcraft," "black magic," "Tarot," "occult," "necromancy," and so on. You will get hundreds or thousands of books on each search. Click on the setting on the left that says "always available." That will narrow them down to ones you can freely download. I suggest you download in PDF format because it preserves the actual page layouts and page numbers of the original books. Have fun.