Can you buy paint for plastic?
Standard exterior gloss paint is a suitable finish for plastic when used in conjunction with an appropriate primer and undercoat. Either acrylic or oil-based gloss can be used, and both are available in a wide range of colours.
What kind of paint do you use on a controller? You can also use acrylic spray paint, but that will cover most of the controller. If you want to paint designs or even different color blocks, regular acrylic paint is the way to go.