Wallcat - Enjoy a new, beautiful wallpaper, every day.
Splashify - Beautiful desktop wallpapers for Mac and Windows
Unsplash Wallpapers for Mac (Official) - Curated, HD desktop background photos from Unsplash.
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.
Wallpaper Wizard - Wow-worthy backgrounds for Mac
WLPPR - Beautiful mobile wallpapers made from satellite imagery