I am looking to buy footballl cards, and it has been years since I bought, which ones are best?

My son is starting to get interested in collecting, but he is very young. I was looking to see whats the best cards to buy that have the most value. I don't want to get ones that are over produced. I want to get the ones that has the potential for the most valuable.

He is interested in Football cards, and I bought Panini because it had 4 autographs per box. Little did I know that the box only came with 4 cards. So I need help to pick something that has a lot of cards so the ones that are normal with little no to value, my son can collect. (He is too young to understand value yet), and the ones that have some value, I can store them away. Looking for recent ones too. I have my own huge collection of older cards. Thanks