The most common design for a business card at any given point in time would be a white background with black text on it in some way, shape or form. While this is a tried and tested method for you to getting the message across to the various people that might be out there, it is also essential for you to try your best to keep in mind that inverted colors can go a long way as well. A big part of the reason why that is the case has to do with the fact that when you hand someone a card that has inverted colors on it, their first impression of you would be that you most likely run a highly disruptive and experimental business model and this would make them want to work with you or perhaps purchase products or services from you on a more or less regular basis.
The main premise of inverted colors is that you would print Black Metal Cards and then have white text placed upon them. Your first reaction to this type of design would be that of shock as well as a little bit of dismay since it would throw you for a loop and you would really struggle to wrap your head around it, but suffice it to say that if you stick with this type of design it can end up doing a lot of really amazing things for you.
The best thing to keep in mind about this type of color scheme is that virtually no one is doing it right now, which means that you are in a position to truly innovate on a scale that has never been seen before.