Promo.com - Every promotion starts with Promo.com.
Splashy - Breathtaking, auto changing wallpaper app for macOS, Windows, Linux, iOS & Android
ImageKit.io - Instant multi-platform image optimization
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.
Assetizr - A super fast image resizing tool
Splashify - Beautiful desktop wallpapers for Mac and Windows