I evalled all pieces of Javascript of <30 characters in Rhino, takes 1 minute on my laptop. 4219 possible values, after stripping out some really uninteresting stuff. Doesn't seem to contain anything interesting, unfortunately.
I am not sure about those results. I entered (+[][{}]+{})[+[]] into Chrome console and got N (from NaN[Object object]) while your code lists it as u. If you replace the first +[] with a 0 you get an u (from undefined...). Interesting.
http://pastebin.com/CM5ac6Xi