If you're looking for something truly fresh and out of the ordinary, then in addition to classic motorcycle wallpapers, you can consider a slightly different approach - stylized backgrounds. For example, I recently came across wallpaper geometric design from
https://fancywalls.eu/wallpaper-pattern/geometric-wallpaper/ - they not only have high quality and clarity, but also a modern, dynamic style that goes well with biker aesthetics.
They, of course, do not have direct photos of motorcycles, but some patterns in the spirit of carbon fiber or techno design look very cool in the interior of a garage, workshop or even a play area. If you want something truly original - this is definitely worth a look.