I've never been one to do a lot of courses and certifications and such. But I wanted to learn more around Node.js and work on expanding my assorted JS skillset out from just "and now a form pops up over the whole page" to be able to touch on more areas. So I took the Introduction to Node.js course that The Linux Foundation posted to edX.
It never dives super deep into stuff (it is an intro level course), but it was nice to see some more options for how and where JS can be used to expand out into other areas. They touched on APIs, websockets, command line tools. All in all, a pretty good overview.