What's a book that started out similar to another book/series you've heard of or read but slowly became its own story?

[˚༚✧ ☆ Eliza]

I've encountered some of these types of books. I want to know a book you've read like this and your thoughts on this. Do you like when books do this or do you preferer them not to be like this? I'll start with mine:
The Crowns of Croswald (I think that's how you spell it.) It started out very similar to Harry Potter in many ways. But then all this stuff happened and made it developed more and it changed in a way I liked. I don't usually like books like this, but this one was okay.