The biggest problem I have with lists of links like this, is that there is vary rarely a hint to the quality of the resource behind the link. Is the book being recommended because it is a great book or just because it is free.
I started recommending the books just because they're free but realized pretty much all are at least okay or good, there don't seem to be many bad ones among the freebies. Maybe because writing a book and making it public takes deliberate and considerable effort, so only motivated authors do it.
Some of the books I used are "Code with Repl.it", "Tpython 101", "Boxes", "Clean Architectures in Python", and "The Hitchhiker’s Guide to Python".
I highly recommend "Boxes: Your Second Python Book" because it's unlike any other book I've seen. It focuses on text layout algorithms and builds an increasingly advanced exmaple through successive iterations.
