John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads

Wallpaper Engine - Wallpaper Engine enables you to use live wallpapers on your Windows desktop.

Muzei - Muzei is a live wallpaper that gently refreshes your home screen each day with famous works of art.

Video Paper - Set a video as your wallpaper.

Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.

Plastuer - Plastuer is a Windows application for setting GIFs, videos, and web pages as your wallpaper.