The standard.
OP - not to generalize but when most hobbyist are looking at damsels the more often genus to search is Chrysiptera. The over arching theme with this genus is that they are more friendly, less aggressive, and good for mixed systems. Azures, Talbots, Starcki, etc. I know you are asking about color but you could always do a search through the genus to see what strikes your fancy.
I've kept Azures which I found to be colorful as they mature. The scale contrast really stood out along with the color separation. My Talbots, while I didn't own them long, had a lighter coloration but stood out among the reef. I lost these during a massive bubble tip spawning session while I was out but they all got along otherwise.
I have kept 7 Sapphire damsels and they had amazing color. Males during spawning looked great. The only problem with these damsels is that the male gets very, very, protective of the egg nest which causes some problems. I trapped and gave these away. A bit sad but I should have added them last.
I currently have 11 Lyretail Damsels. They will not stand out with color but they are very active in the reef. They are black with a light blue on the lower fin. Tail inner has yellow. They stand out as they move about the reef but at a distance you wouldn't notice them.
I guess I was just trying to say that you can look in the Chrysiptera genus for what we, hobbyist, typically aim for. Starcki's are more expensive but the standard as they are beautiful. Azures, Talbots, Randals, and others are also pretty. Have a system set up with a lot of rock work, mature corals, and space a damsel is a great addition. In my opinion and experience.
