I received a holiday bonus in the form of a gift card. How do I report the amount on my return?

Your employer should have included the value of the gift card as part of your wages on your W-2.  You would not need to add it anywhere else on your tax return.

For more information, take a look at this information from the IRS:  https://www.irs.gov/government-entities/federal-state-local-governments/de-minimis-fringe-benefits