Fancy rat
Fancy rats have been bred as pets at least since the late 19th century. They can have many different colors and coat types.  They are sociable, intelligent animals. They can learn to come when called, use a litter box, and do many different tricks. Pet rats act differently from rats found in nature. The number of generations since they have been removed from the wild and how they were bred has an effect on how much they act differently. They are not any more of a health risk than other common pets.