There have been several well-done design guides produced this year (e.g. Google's Material). It seems to be the thing to do these days. Design guides are a great chance for design teams to show off all the detail and thought that went into their work. I especially like them because they arfully show how interconnected and intricate digital experiences are now. The most recent one I've seen is the IBM Design Language. Even though it is tailored for IBM, it can read as a "best practices guide" for many aspects of design work (visual, experiential, technological, etc.). The "Famework" section is the place to be if their navigation options confuse you (as they did me). I hope you enjoy it as much as I do.