What are some novels you've read that completely break the boundaries of what a novel should have/be?

Inspired by reading (and finally finishing after many false starts) If On A Winters Night A Traveller by Italo Calvino. I got to wondering about the things we take for granted as being part of a novel (e.g. a named protagonist) that might not be needed.

I also recently read Robinson Crusoe, which was apparently one of the earliest examples of realistic fiction with a protagonist with biographical details. Previously most novels were apparently set "once upon a time, far far away" with a protagonist with no set biographical details.

I wonder if there are any real boundaries in novel writing left to break - there are novels from animals perspectives, novels without a linear structure, etc. Are there any really unique novels that have come out recently?