If your looking to do a dark green maybe
dark angels green.
Blue id use either midnight blue or regal blue.
for red probably red gore im not sure if you can go darker then red gore.
or even a dark purple could be nicely contrasted Liche purple maybe!!
to highlight the colours add a lighter shade of that colour.
For e.g. to highlight regal blue or midnight blue add in ice blue.
You probably already know this but if you dont i hope it helps!!!
