I think there could be many people who would benefit from ideas about this problem.
So much depends on the precis rules of one's HOA. This thread about
creative downspouts has some that might qualify as "art work" which is sometimes an allowable exemption. It also has some that are likely to cause trouble, so use common sense!
However, if artwork is out, I'd be looking at beautiful trellising and vines or possibly espalier trees that are allowed in the area. We are allowed large water tanks in our ecosystem, but honestly, they don't qualify as pretty. Trellising and adding plants would improve them so much that I would want to do so both for the beauty and the benefits of vertical garden space.