An other thing is if your pcb has lock light you may want to follow that color (or change it, i have now a model M with pink LED and a Dell with reds, if it is through holes not that hard, if it is smd a bit harder but still feasable).
Other than that i would probably go with a cool color, maybe a deep or electric blue or a purple or maybe even a grass/jade/english green, for accent over a black vivid colors are usually what i like so i may not be the best person to help you with finding more subtle colors.
The problem might be finding them, i have no idea on where to find colored cherry pbt caps i tried tinting mine but right now i am struggling with blacks looking brown and i still need to try adding legends to get light on black for a M.