Wallcat - Enjoy a new, beautiful wallpaper, every day.
Wallhaven - Your source for the best high quality wallpapers on the Net!
Splashify - Beautiful desktop wallpapers for Mac and Windows
InterfaceLIFT - High-resolution widescreen wallpapers, desktop icons, and themes for Mac OS X, Microsoft Windows...
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.
Ultra HD Wallpapers - One site with wallpapers at high resolutions (UHD 5K, ultra HD 4K 3840x2160, full HD 1920x1080) for phones and desktop. Download 4k backgrounds to bring personality in your devices.