Font Book has Smart Collections, which allows you to filter based on font properties. I created a Smart Collection with the filter "Languages include:"
It works if I enter "French" or "Japanese", but if I use "Chinese", there are no results.
I looked in a Chinese font's properties (e.g. Baoli SC), and it lists "Chinese (Simplified)" under Languages. I tried all of these search terms, but none worked:
Chinese Chinese* Chinese (Traditional) Chinese (Simplified) Traditional *Traditional* Simplified *Simplified*
It seems to me a major oversight/bug that Font Book's Smart Collection filter cannot search for a term that has spaces in it. (Or is there a way to "escape" a space?)
Side note: In Yosemite, some of the Chinese fonts' Language properties have "Chinese, Chinese (Simplified)", so those will show up if you do a Smart Collection for "Chinese", but not "Chinese (Simplified)". In Sierra, however, none of the Chinese fonts' Language properties has "Chinese" alone.