I published a new category on my site with a collection of useful game development resources to learn the art and craft of developing games. I try to highlight sites that are not as obvious, and especially articles I stumbled upon when implementing specific features (like procedural map generation), which helped me to better grasp certain aspects (like maths).
The collection of course materials from the ITU Copenhagen is especially noteworthy.
I will update this site whenever I find anything that is useful and relevant for game development.