Google Photos - All your photos are backed up safely, organized and labeled automatically, so you can find them fast, and share them how you like.

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

Trickster - Keep track of recent files on your Mac

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

Zebra - Zebra builds enterprise-level data capture and automatic identification solutions that provide businesses with operational visibility.

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