Couldn’t find any on the site.
You can find some concept art and screenshots here: https://blizzard.gamespress.com/Diablo-IV---BlizzCon-2019-Press-Kit
Some good folks over at Reddit have already thrown a few backgrounds/wallpapers together. I won’t presume to tell you which ones to pick, but a search of the Diablo sub-reddit for the phrases ‘background’ or ‘wallpaper’ throws up a few beauties.
I’ve already stolen this one to use for myself: https://d29z11wvk6phpt.cloudfront.net/assets/images/Story-Ultra.7833a3f4b6c844c180132dd947bbe11e.jpg
https://www.flickr.com/photos/168993394@N07/sets/72157711616028178/
Thanks for this, will use them
Hey Guys, please check my new 4K Wallpaper, have fun