Javascript

Frameworks/Extensions:

Moment - Date/time extension
Underscore - Extension that provides some functional programming features (map, filter, reduce, partial)
Ramda - Deeper functional extension
Flow - Static type checker
Quintus or Phaser - Game Frameworks

Learning:

You Don't Know JS
Eloquent Javascript
Game Tutorial - Simple multiplayer car game
Dependency Management
Javascript Trends 2018
Javascript Testing
Angular Heroes Tutorial
Angular Beginners Guide - Flag descriptions and component explanations

Notes:

Self-Executing Anonymous Function or Immediately Invoked Function Expression - By wrapping an anonymous function in parentheses and then invoking it, it allows code to be run without overwriting functions or variables in other contexts.