I've always thought that dyes have been an interesting aspect of GW2, giving players a lot of different options for coloring their characters. However, compared to weapon and armor skins, there are no achievements or titles for collecting them. Given that the majority of them are acquired through random chance, collecting all of them would certainly be an achievement in my mind. Especially since other than cosmetic choices and selling on the TP they hold no value. This would give players another incentive to unlock them, adding to their achievement points and a unique title like "Dye Hard Collector" or something like that.