I
found two. First one focuses on silhouettes and color, whereas the second goes more into how the shapes accurately reflect characters' hitboxes and the like.
This might be bias talking because the game taught me to like clean, simple designs, but I still consider the base game to be the gold standard in art design. Not just in longevity (it started to show its age a couple years ago, but that's not bad for a nearly two-decades-old game) but in terms of integration and direction. They put so much thought into it, from themes to silhouettes to values to focal points, that the second accessories got out of control it hurt the careful balances all the more. This is because, at the time, Valve understood that in design, especially game design, everything has a purpose.
To bring this post back on topic, I understand that designing for video games is different from comics, animation, etc. Whether you think it's to craft an experience or say something about society (bottom text), it's not about playing dollhouse with your OCs and doing whatever you want. It's "does this do anything." Does it work towards conveying what you're trying to say? Does it hold up under scrutiny, or does it work against you? That's what any artist should ask himself. I have half a mind to show that Dobson comic about the audience seeing apples vs pears but I can't find it.