This statistics professor wrote a calculus textbook that is essentially a fantasy novel. The protagonist finds himself in a mythical kingdom and uses the principles of basic calculus to help solve people’s problems. I just got started on it and so far it seems helpful for putting abstract concepts into practical spaces, so it’s good for self-teaching/self-paced learning of calculus. Plus it’s about 5% the cost of a college calculus textbook. I got mine on Amazon.