If you live in the US, you now have access to a new My Nintendo reward theme in the form of Metroid: Samus Returns for your 3DS. The theme was released in Japan recently, and there is still no sight of the theme in Europe. It can be acquired for 20 gold coins, which can be obtained by purchasing digital games via the Nintendo eShop on 3DS, Wii U and Switch. Check out a video of the theme in action below!
Source: My Nintendo