Really, no one cares about the layout of credits, as long as you include everyone that you can in your final product as don't phrase it as though they endorse your project or "helped you to make" the resources. I personally would be pissed if I made a resource that someone used in a shitty game, and then they put me in the credits as "PEOPLE ON MY TEAM WHO MADE THIS GAME!" or "Zylos helped me to create such and such resource" when really you had nothing to do with it. Other than that, I don't think people care too much, though even then you have to be careful and check the terms of using any particular resource. Some people actually require you to ask them specifically for permission first, though that's usually just for posting their resource on other websites.