iStat Menus - "An advanced Mac system monitor for your menubar."
Splashy - Breathtaking, auto changing wallpaper app for macOS, Windows, Linux, iOS & Android
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.
Splashify - Beautiful desktop wallpapers for Mac and Windows
Stats - Simple macOS system monitor in your menu bar.
Übersicht - Keep an eye on what is happening on your machine and in the World.