For now, I'm just going to link to one thing. I found out that a beloved book from my childhood, titled "My Father's Dragon", is officially in the public domain! It's a very cute book, but I *do* wish to warn that there's a very brief reference to corporal punishment in the first chapter. (This book was first published back in 1948, to be clear.)
You can read it HERE.
There are two sequels, which are also great, but they unfortunately aren't in the public domain yet. If you want to buy them, or borrow them from a library, the title of book #2 is "Elmer and the Dragon", and book #3 is "The Dragons of Blueland".