It's a tough question that we all think about at least once, and I just don't think it's possible to think of another one. But there are actually many more colors on Earth than the ones we see. Some animals can actually see more colors than we can. But unless we surgically attach those animal eyes to our heads, or make special glasses, good luck seeing them.
However, I do sometimes wonder if an object that was a color we've never seen before and it was discovered, how would we see it? Would we see this color?
Heavy thinking. Heavy thinking.