I would be really nice if it was possible to create your own visualizations with simple Python code instead of writing a whole new panel/plugin. You write in the FAQ that you are working on making it easier to add new visualizations to the framework, and I hope you will consider this idea. I imaging a visualisation type/plugin called Python code, where you can add a data source, and then you can write any python code that outputs a html visualization using the data source. You can take a look at powerbi, where one can add both custom r and python visualizations (although the panels don't support html-outputs here).

Thanks @tobiasdirksen , This is a great idea worth exploring 馃憤 If you have any suggestions for how this should work in practice in the context of Superset I encourage posting here to get the discussion started.
Hi if we are having Jupyter notebook like component for processing this visualisations in the superset
Is there documentation to create custom panels and data sources in wiki pages? We have done a lot of panels and data sources for Grafana, looking forward to adapt superset for few projects.
Recent blog post explaining how to create plugins.
https://preset.io/blog/2020-07-02-hello-world/
Plugins are now 100% defined in javascript. We can improve the /api/v1/query endpoint that is implemented in Python to do more pre-processing of data in the backend, but all visualizations will be defined in JS/TS from this point on.
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Thanks @tobiasdirksen , This is a great idea worth exploring 馃憤 If you have any suggestions for how this should work in practice in the context of Superset I encourage posting here to get the discussion started.