James Cameron certainly created a beautiful "reality" in his Alpha Centauri moon world. Of the fictional races, I like the Navi, but I also liked the Tymbrimi of David Brin's "Uplift" universe.
But looking at reality, perhaps the most "beautiful" non-human race were the Neanderthals -- the "daughters of men" of Genesis 6. They were so "fetching" and "hot" that human males wanted to tie the knot. But this betrayed God's plan for us. Why? Because Neanderthals and their hybrid offspring did not have the mental capacity to build civilization. Their lesser brains could only think of selfish things continuously. They couldn't fathom things like forgiveness and inspiration. They would never be able to understand our spiritual nature which needs nurturing and awakening. And that's why God, in His wisdom, chose to wipe out a crop of Homo sapiens along with the Neanderthals, so that His invisible children would have a chance at awakening.