I've been look to design a credit card icon set for a while and finally had a chance to do it. Most of the icon sets I found just weren't sharp enough and overly stylized. What I needed was a crisp set of simple icons that would also be scaleable for retina displays. You know how it goes from there... once you set your mind to it, you just have to get it done!
For best preview check @2x version. PSD also includes 4 additional credit card icons. All icons are scalable vectors with layer styles. You can use it for any purpose including commercial. Attribution is appreciated, but not required. Enjoy!