Alternatives to underscore.js

I know this is old but did you look at lodash? From the site:

A drop-in replacement* for Underscore.js. [...]

Custom builds make it easy to create lightweight versions of Lo-Dash containing only the methods you need. To top it off, we handle all method dependency and alias mapping for you.

Take a look at lazy.js (http://dtao.github.io/lazy.js/) similar to underscore.js but with significant performance improvment due to lazy evaluation