Industrial standard color is Green, if you choose that color you save cost and time.
We know there are laminate type and project that require differents colors,
example is metal core pcb type (alluminium pcb for lighting purposes), for that,
in our configurator there are other colors option that you can choose.
About Solder Mask design, there are dfferents rule between green color and others differents colors.
in our pcb configurator you can order differents colors.