In the demo, “OGL” also seems interesting, but it obviously will take some time to test the ones you suggested and the one I have found to really understand what they do and how to use them. I know you are not recommending buttons, such as GenericButtons and ButtonPanel, but I like their look anyway.
As a side note, I could use HTML2_WebView as I already know how to make visualizations with JavaScript without using any JavaScript libraries. Using my Python application as a web browser (HTML file renderer) seems interesting even though I probably will not use the application that way.