Game development is passion for many developers and courses about it are very important for everyone decided to be in this niche. Here is a compilation of several good free courses that are going to start soon or are constantly available. Learning to make games is a long and hard process and requires a lot of studding and practice. I hope those resources will help you in that path.
Introduction to Game Development by Michigan State University
Good game development course with Unity3D and C#. In this course you will create your first Unity3D game from start to finish. Good start if you want to make games.
Beginning Game Programming with C# by University of Colorado System
Good choice to start. In this course you can learn MonoGame and C# and will create fun games. You can improve your C# skills on this course too.
Game Design Courses
Introduction to Game Design by California Institute of the Arts
This course presents you with the primary concepts of gaming and game design. If you want to make career in the game design field or just improve your indie games, this course may be useful for you.
Game Design Courses by MIT Open Courseware
Many useful resources on game design and development. One of the best sources of knowledge on the internet.