Problem

There are a lot of proposed styles on https://matplotlib.org/stable/gallery/style_sheets/style_sheets_reference.html but most of them are light theme: a single dark theme exists against almost 30 light, and let's be honest it's not one that has received a lot of love. I submitted a quick fix to make it viable with a grid (#23598) but it's not going to fix the core issue, that is the lack of dark themes available.

The dark_background is also pretty bland: using "black" is typically the most aggressive background you could pick for a "dark" theme, it doesn't need to be.

Proposed solution

Maybe https://github.com/chriskempson/base16 (for example) could be used as a foundation for adding more dark flavors?