Full featured Promises/A+ implementation with exceptionally good performance
A logger for just about everything.
Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.
Handlebars provides the power necessary to let you build semantic templates effectively with no frustration
Streams3, a user-land copy of the stream library from Node.js
a little globber
yargs the modern, pirate-themed, successor to optimist.
Parse, validate, manipulate, and display dates