My suggestion isn't exactly a "theme" per se but this thread seemed to be the best fit.
Please stop putting bases under the floor decorations. Just leave them blank. That way we're not stuck choosing between putting down grass or not using the decor. Even the ones with flooring don't always work well with what we have available for flooring. Sometimes the base can pass as a throw rug under the decor but sometimes it clashes especially if it's a platform.