What are the jackets that football players wear over their pads when it's cold
Those apparel are commonly known as sideline jackets (over the pad player jackets). They are specially designed to accommodate shoulder pads as well as having extra room in the hood to accommodate a helmet.
For regular wear (off the field) you can find a great selection of NFL sideline jackets at the NFL Shop - Sideline Jackets.
Speaking of jacket, an Apollo astronaut, looking to keep the "right stuff" forefront in the public's eye, has recreated his iconic NASA-issued blue flight jacket down to the last button. Find out more at Space.com.