WallpapersEveryday - Gorgeous wallpapers on your desktop in just one click or auto-delivered at chosen time intervals.
AutoWallpaper - Using AutoWallpaper:
Ruler for Windows - It's a screen ruler for Windows.
Becrux Wally - Wally is a Qt4 wallpaper changer, using multiple sources like files, folders, FTP remote folders, Flickr, Panoramio, Ipernity, Photobucket, Buzznet, Picasa, Smugmug, Google, Vladstudio and deviantART images. Now it's available in many languages!!
Fondo - Find the most beautiful wallpapers from Unsplash.com
Pixiv for Muzei 3 - Best Pixiv plugin for Muzei 3