Level Design Courses
LCI Education via edX Types of Games in Level Design
LCI Education via edX Shooters and Game Engines in Level Design
LCI Education via edX DOOM's Development - A Year of Madness
WeAreDevelopers via YouTube Introduction to Level Design
LCI Education via edX Prince of Persia Game Development Tutorial
Envato Tuts+ via YouTube Gamer Character Creation Tutorial
Envato Tuts+ via YouTube An Introduction to Valve's Source SDK - Entities
Envato Tuts+ via YouTube Introduction to Valve's Source SDK - Textures
Envato Tuts+ via YouTube Introduction to Valve's Source SDK - Overview and Brushes - Part 2
Envato Tuts+ via YouTube