Adding custom charts

For the needs of our client, we would like to build custom chart’s into Metabase. More specifically, our top priority is making a Sankey diagram in Metabase:
Does anybody have experience in achieving something similiar, what was your experience in customly modifiying Metabase and any suggestions that you might have? I found only one thread so far about this:
Anyone achieved this already and has some good tips&tricks to share?
Thank you!

I use metabase for very simple charting and the pulse features. (which are awesome by the way team).

For Sankey Diagrams and most complex/ product focussed visualisations I use Airbnb Superset. It is now in Apache incubator meaning it will get more support and improvements over time too

Sankey diagrams are one of the key visualisation components of this but in general Superset doesn’t have the ease of use of Metabase and how data is broken down into questions instead of queries.