Beside all major races, ancient races and minor races, the galaxy of Stellaris is roamed by a number of unique races. They are shown in purple and do not posses any planets, but just a space station shown on the map with tower banner. There are 3 of them. Trader - which gives a resource and allow trading minerals for credits and vice versa. Scientists, which give the science bonuses and lend the Scientist Leader. And cultural, which gives some unique options with culture and sell happiness buildings.