Node JS, traditional data structures? (such as Set, etc), anything like Java.util for node?

es6 has a Set class built in:

new Set([iterable]);

see: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set

Collections.js has Lists, Maps, Queues, Sets, and Heaps, all with consistent interfaces. Github.

it seems JavaScript is lacking traditional data structures...

Yes, this is javascript, the very concept and implementation of data structure is done quite differently from languages like Java.

I'm not sure that you're really going to find what you're looking for with Javascript. Howver, there are some libraries like underscore that should make it easier to build the type of structures that you want.