As far as I know and have seen those colors you mentioned are the only colors that occur in Xenia. Are you thinking of firework polyps? Those have a similar appearance to Xenia but they are much more colorful, you can also find them on pretty much any online coral shop.
I too love easy colorful corals! I believe firework polyps are fairly low maintenance (star polyps also are easy and come in a nice neon green), zoa's are easy and come in a variety of crazy colors, hammer corals and torch colors are also super colorful and have a lot of movement, there's a lot of variety and color among ricco corals. Hope this helps!I'm mostly just looking for low maintenance corals with bright colors as this is my son's tank and the more colors the better in his book!