I do not have a well-organized one, especially specific to JS. I have my favorite set that I personally like over the years. I think at least a couple are from "The Practice of Programming" by Kernighan and Pike; I especially like the Markov-style text generator -- their well-written solution for the same problem in Java, C++, Perl and Awk provides a good perspective, too. Since my background is in math I like prime decompositions, Lissajous curves, drawing fractals, building mazes. But those are just personal preferences suitable to many general-purpose languages.