THE ODIN PROJECT theodinproject.com

The odin Project is open source and is the best for beginners or those who have tried other resources without success, who want to work as a web developer ,do freelancing work, build a startup or learn to build a website.

CSS-TRICKS css-tricks.com

Definately check out this website because you can get lots of tweaks and tricks about the cascading style sheets(CSS). There are a bunch of articles,videos and books are available on their site.

30 SECONDS OF CODE 30secondsofcode.org

This website provides short code snippets for all your development needs and makes work easier in very less time. You can search by name,tag,language or using a snippet's description.

FRONTEND MENTOR frontendmentor.io

Frontend mentor is a must for those who are looking to practice and enhance their frontend skills. You'll get cool challenges to improve your skills.

CODEMYUI codemyui.com

This website is very simple and it provides some awesome snippets which you can use in your projects. CodeMyUI is has really cool repository for CSS snippets,HTML elements and Javascript snippets.