Decoration only: neckties. Decorative and fulfillimg a function: Cufflinks.
Of course women have more of the Decoration only type. I remember a co worker who came to work in a blouse wit two rows of buttons all down the front. but none of the buttons were buttoned. the fabric was sewn together under them. The real opening was a zipper down the back
The watch I wear is both decorative and functional. While I do use it to tell time, I also have my phone for that, so it isn't completely necessary, and certainly a large part of why I wear one is because I like the way it looks.
A hat, which I occasionally wear, is completely decorative for me.
Paynuts 