Surprise to see this at the top, I am the creator* of plotnine. The most common question seems to be, what to expect of plotnine? The answer; a high quality implementation of a grammar of graphics with an API that closely matches ggplot2, and more.

I also want other packages to be able to build off of plotnine, e.g. a package with the functionality of Seaborn could be built off of plotnine. The only constraint should be whether the backend -- in this case Matplotlib -- does stand in the way. Matplotlib is evolving (though slowly) and has a very receptive community so there is lots of hope.

* - Many people contributed to its history.