John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
DisplayFusion - DisplayFusion will make your multi-monitor life much easier.
Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.
Dual Monitor Tools - Download Dual Monitor Tools for free. Tools for Windows users with dual or multiple monitors. Tools for Windows users with dual or .
Wallpaper Cycler - NuonSoft WallpaperCycler is a powerfull utility to manage all your wallpapers and to automatically cycle between your wallpapers.
Muzei - Muzei is a live wallpaper that gently refreshes your home screen each day with famous works of art.