Personally I have been using this one https://getwallpapers.com/wallpaper/full/e/3/d/1515937-dark-windows-10-wallpaper-2560x1920-windows-10.jpg
Personally I have been using this one https://getwallpapers.com/wallpaper/full/e/3/d/1515937-dark-windows-10-wallpaper-2560x1920-windows-10.jpg
I kept this one, even after upgrading to F39 https://fedoraproject.org/wiki/File:F38-01-night.jpg