I recently heard the last 30 seconds of an NPR broadcast about the Internet Archives at https://archive.org. I then goggled “internet archives” and you should see what’s there! It’s a nonprofit with over 284 billion web pages doing this.
There are Maine genealogy books, city directories, census records and you name it. Pick a state; pick the European libraries or the Library of Congress. You name it. I only went on to see if I could figure out how to use it and to look at the selections. I picked a book and looked page by page. Who knows what useful information might be found there.