Adapta KDE - This is a port of the popular GTK theme Adapta for Plasma 5 desktop with a few additions and extras. RECOMMEND USE THIS CUSTOMIZATION WITH KVANTUM ENGINE: https://www.opendesktop.org/p/1005410/ https://github.com/tsujan/Kvantum/releases
To install Appimages from Appimagehub via CLI use appimage-cli-tool. This allows you to e.g. search appimages with "app search xyz" and install any appimage via command "app install #id".
If you are a developer who is interested to easily build appimages from your code repo, read the guide here.
Global Themes in Plasma are Meta- or Super-Themes, capable of changing multiple aspects of the desktop environment at once, like Window Decoration, Plasma Theme, Color Scheme, Icon Theme etc. In addition, one can define the complete Layout, like what panel to use where, the menu type used and much more.