Source (link to git-repo or to original if based on someone elses unmodified work): https://github.com/Zren/plasma-wallpapers/tree/master/animatedhue
A wallpaper plugin for Plasma5 that changes the wallpaper hue smoothly every few seconds.
I personally change the hue by 0.05 every 60 seconds which would take 20 minutes to cycle the entire colour wheel.
Download, then run:
kpackagetool5 -t Plasma/Wallpaper -i ~/Downloads/animatedhue-v1.zip
Reddit Discussion: https://www.reddit.com/r/kde/comments/6yz676/