If you have a zero balance on a credit card when you file, this account does not have to be listed since it is not a debt that is owed. From a practical standpoint, however, it is likely that the credit card provider will cancel your credit privileges once the bankruptcy is reported to your credit. Credit card companies routinely monitor credit reports and a bankruptcy filing will generally trigger cancellation of the credit account.
Debtors who want to keep a credit card after the bankruptcy may be able to reaffirm the debt, but this is not a course of action that I would recommend. Reaffirming a debt obligates you to repay it despite the bankruptcy, and essentially defeats the benefit of a discharge with respect to that debt. Moreover, most credit card providers who will entertain reaffirming a debt will require that you repay the full balance on the account before they will reactivate the card to allow post-petition charges. There are many ways to reestablish credit after a bankruptcy filing and those options should be explored post-discharge instead of weighing down your fresh start with debt that must be repaid.