Hey there Kameneko, probably not what you had in mind but this game art "trick" is more of method to speed up your drawings. I was getting tired of it taking forever to draw a character's head and have it be consistent with the rest of the drawings in my games so I decided to 3d model the heads(and later, make simple bodies) so that way I could keep things consistent from all angles. For my current project, it was especially crucial since I was dealing with a character who's head was so oddly shaped...
First, I draw a sketch of the character's head(or the entire body sometimes but I already knew what kind of body he'd have) then I make a 3d model and try to match the proportions and overall look as closely as I can to my original drawing.
(This is the first ever picture of the triceratops and also a very early version of the head, I've made adjustments and improvements since)
As you can see I also used a simple texture to show were face/head markings will be drawn.
Then, I draw over the 3d helper with the stuff that brings the character to life! But very lightly. I'll usually refine a couple things or use another 3d helper for the hands(I have a separate model for that)
Next I draw the line art. :3 I also fill in the markings/important colored areas because sometimes it's really important to show the depth of the face's structure(like the beak)
Finally color!
You might think it's more time consuming to do things this way- and yeah perhaps if you're already a skilled enough artist! But it just takes me too long to draw perspective lines, draw guides and even when I did all of that, without my current method, my art wasn't at the quality I'd like. So not only does this have the benefit of speeding things up for me, but it's also improved the end result of my art a ton! So I can have more art in my games and it's also better art :3
So if you're a decent 3d modeler and a decent 2d artist, I'd recommend combining the two in anyway you can to help with creating better 2d art more quickly. This doesn't just have to be for games- it can be for stand alone artworks, but it'd be especially useful if you were doing a comic. Any situation where you're drawing the same character a lot really.