Browser support
Also list feature support, usage and how to detect support
General
A curated list of awesome WebGL libraries, resources and much more (github)
List of WebGL frameworks (Wikipedia)
Learning and reference
WebGL Fundamentals
WebGL from the ground up. No magic.
WebGL 2 Fundamentals
WebGL2 from the ground up. No magic.
Learning WebGL
Learning WebGL
Learning Three.js
Learning Three.js
Online courses (video)
Interactive 3D Graphics: Creating Virtual Worlds
Udacity.com/course/cs291
Interactive Computer Graphics with WebGL (Angel)
Coursera.org/Course/WebGL
Introduction to WebGL 3D with HTML5 and Babylon.js
MicrosoftVirtualAcademy.com/Training-Courses/Introduction-To-WebGL-3D-with-HTML5-and-Babylon-js
Computer Graphics (UC San Diego)
edx.org/course/computer-graphics-uc-san-diegox-cse167x
Foundations of Computer Graphics (BerkeleyX)
courses.edx.org/courses/BerkeleyX/CS184.1x/2012_Fall/
Inspectors and Debuggers
Spector.js
Spector.js is a WebGL debugger that you can use to debug any WebGL context (including WebGL2).
https://spector.babylonjs.com/
WebGL GLSL Shader Editor Extension for Google Chrome
A Chrome DevTools extension to help you edit shaders live in the browser.
https://github.com/spite/ShaderEditorExtension
WebGL Inspector
WebGL Inspector is a tool inspired by gDEBugger and PIX with the goal of making the development of advanced WebGL applications easier.
https://github.com/benvanik/WebGL-Inspector
Online Utilities
Normal map online
Normal Map Online
cpetry.github.io/NormalMap-Online/
Texture generator online
Textue Generator Online
cpetry.github.io/TextureGenerator-Online/