Color combinations

As I'm building my DE army, I've yet to touch painting or priming them. However I'm not sure how I want to paint them fully I plan on doing the black w/ highlights. I've been leaning to Black/Purple theme, I'm hesitant towards any red or blue as I see that commonly. Just looking for any ideas or opinions and in general any tips on painting. If it helps at all the RP name I'm placing on them is the Kabal of the Void Sun.

Here, its an internet site where you can find complimentary colors in 4 methods.
https://kuler.adobe.com/create/color-wheel/

Purple and black, that looks like this. Gory Red + Golden Yellow for second set of prime colors, bright toxic green for little details. Bright metal for spikes.