KDE Plasma is a fantastic desktop environment. It is popular for its feature set that allows a user to customize the experience, add widgets, and multiply the usefulness of the desktop with various elements.
When you get started, you already have certain widgets in place to access things. You can customize/remove them or add some more pre-installed ones. In either case, you can also download widgets from the KDE store and try them out.
Here, I mention some of my favorite picks among the default, pre-installed, and downloadable widgets.
Panel colourizer is the only new thing I found. Will try. Thanks.