More Board Surface Color / Surfaces

What Feature would you like to see included within TaleSpire?
What does it look like, how does it work, how is it used. Paint us a figurative picture.

I would like the option to either have custom HSV sliders or at the very least more colors to choose from for the board’s surface. I want to be able to make maps that have mysterious fluids, lava, or even a astral plane feel to them, but the colors are currently very limiting.

What situations would this Feature be useful?
Descriptions, examples, interactions with existing features - whatever you can think of to get your idea across!

I think this feature would be useful for making more varied map locations with better immersion.

Additional Thoughts/Details

Bonus points if the water can also have different textures, colors, etc.