No, of course not every book. But just off the top of my head, I know that Dragon Masters recently had a nonbinary character, and the latest Wild Robot book that just came out (#3) has a fish that changes gender and a whole digression about how the robot main character isn't really female but is "programmed" to feel that way ... I'm sure there are others. As I said in an earlier comment, these led to some unexpected and challenging conversations at bedtime ...
My son spent a lot of his early life visiting doctors and having procedures and hospital stays. In trying to find books to help him process those experiences, I discovered that while there were picture books about hospital stays (broken limbs, maybe a tonsillectomy), there wasn't anything relevant to his medical conditions and the sort of procedures he was undergoing. I spent hours searching the web, asked librarians, etc. It was very frustrating. I don't want to go into the specifics of his medical conditions here.