Many of the types of works that can be copyrighted are very familiar: books, webpages, photographs, music, sculptures.
What some may find interesting is what can Not be copyrighted. Ideas, slogans, recipes, and fashion designs are some of the types on this list.
Go to Copyright Basics to read the U.S. Copyright Office’s definitive take on what can and cannot be copyrighted (p. 3, “What Works Are Protected” and “What is Not Protected by Copyright”). This PDF was written for the general public and is both easily understandable and thorough.