I really seem to like software that's configured with Lua.
It looks nice just as a basic setup (key = value type stuff), but you can do really complex dynamic configurations with it (like the dark-mode config in the linked article).
Hammerspoon is another, you can do so many things with it - I replicated most of Rectangle/Manget with Hammerspoon+Lua myself and now I can do the minor tweaks I couldn't do with the pre-packaged apps.