Over the years I've collected these great pads of paper that I double as wrapping paper. The one pictured is from Idlewild Co. & it's a placemat pad. I think non-cardstock sets of paper used for scrapbooking would be good also.
They're perfect for books. (Fun fact: I work at a bookstore.)
I trim the edges & save it to wrap trinkets, use as gift tags, or to write notes.