Looking up arbitrary ebooks from my library of a couple thousand physical books (accumulated over 40 years from obscure places) on shadow libraries, I get somet

Looking up arbitrary ebooks from my library of a couple thousand physical books (accumulated over 40 years from obscure places) on shadow libraries, I get something like a 90% hit rate. They're almost all English, however, but there are enough nonenglish illicit sources to make me think that "most" is probably right on the money. Also, tbh, from the 10% I can't find maybe 1/5 of those is worth reading. Unfindable stuff tends to be the dregs, although plenty of the dregs are also findable. Recently got into late 19th century Mexican literature, and I find virtually everything I look for. I can find books from small political presses who may have printed only 100 copies. Here's another kink that I have, which basically would have been my most self-indulgent dream as a child: I can look at the ads for other books that are in the backs of 50-200 year-old books, or listings of the rest of the books in a series, and find those books instantly. Between shadow libraries, actual libraries, hobbyist public domain wranglers, etc, it's hard not to find a book.