iStat Menus - "An advanced Mac system monitor for your menubar."
Wallcat - Enjoy a new, beautiful wallpaper, every day.
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.