Wallcat - Enjoy a new, beautiful wallpaper, every day.
Virtual Museums - Explore the world's museums, virtually.
Splashy - Breathtaking, auto changing wallpaper app for macOS, Windows, Linux, iOS & Android
Google Arts & Culture - Explore collections of art and culture from around the world, both past and present.
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.
The Met - Official app of The Metropolitan Museum of Art