Free JS books collection.
Eloquent JavaScript
You Don’t Know JS – A book series on JavaScript
Modular JavaScript
Human JavaScript
JavaScript Enlightenment
Programming JavaScript Applications
JavaScript Garden
Learning JavaScript Design Patterns
JavaScript Allongé, the “Six” Edition
Speaking JavaScript
Understanding ECMAScript 6
Exploring ES6 – Upgrade to the next version of JavaScript
Setting up ES6
Exploring ES2016 and ES2017