John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
Muzei - Muzei is a live wallpaper that gently refreshes your home screen each day with famous works of art.
Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.
Wallpaper Cycler - NuonSoft WallpaperCycler is a powerfull utility to manage all your wallpapers and to automatically cycle between your wallpapers.
Zedge - Huge selection of free ringtones, themes, wallpapers and games for mobile phones. 6.
Folder Marker - Change folder color in two mouse clicks for easy at-a-glance identification.