Nostlan has different themes for every system it supports. If you become a Patreon supporter you can unlock additional themes I've made and even make your own custom themes.

gba: purple (default), blue SP, light blue SP, red SP, silver SP

gcn: purple (default), orange, silver, panasonic Q, black

snes: Super Nintendo (USA) controller (default), Super Famicom / PAL controller, Super Nintendo (USA) console, snes game box

switch: red and blue (default), splatoon 2, animal crossing