So You Want to Learn To Main Tank?

An introductory text, but an excellent one nonetheless. If you do not have any Overwatch tank experience, this guide is a great place to start. It introduces the basic concepts of tanking, as well as providing an overview of the tank characters. Although it is older (it does not contain any Wrecking Ball information) it is nonetheless a great "intro to tanking" style resource.

Creating Space, How to be a Competent and Effective Tank Player

This is an essential tanking guide covering the "SPACE" resource in Overwatch. Space is mostly the domain of Tank characters, who are responsible for its creation and management. Excellent organization and well-written examples make this a must-read guide for any aspiring tank players.