A fancy extension to violin plots.
If the data in a violin plot is ranked, you can visualise the order by gradually subsetting the data from the top of the ranking. By overplotting the violin plots of the decreasing subsets, you get a heatmap inside each violin, which shows the distribution for both the bulk of the data as well as for the top of the ranking.
In the above plot, the bulk distribution is in dark blue/red for the bulk top/bottom of the ranking, and increasingly small subsets from the top/bottom of the ranking are increasingly bright.
The slug plot is introduced in this blog: http://yabib.blogspot.com.au/2016/03/slug-plots.html