I headed up the 2D (Concept Art/UI) team during the development of Phantom for nDreams on Oculus Rift and Quest. During production I and the team produced thousands of sketches to contextualise design ideas, greybox scenes and props, storyboards etc. Here's a few of mine from that time. Note that most real concept art that is done during game production is like this - problem solving with quick sketches and studies to help maintain the flow of work and enable assets to be moved on to the next stage.