It honestly depends on how much $ you want to spend, unfortunately. There are so many different variations within sets now, it will make your head spin. There are cards with actual gold and diamonds on/in them.
Of course will cost you 4 figures to get a "box" which is really like 1 pack with 2 cards or some nonsense. But hey you might get the diamond encrusted Joe Burrow autograph 1/1!
I got Illusions, which is probably one of the lower end sets, but they do have some nice parallels (serial #'d ones, etc.). They do those for football and basketball. I also got a box of Mosaic football, which is a little nicer set (higher value parallels, etc.) and that is a cool looking set to me. They do basketball and football also. I guess the last 2 I'd recommend for bb/fb are Prizm Draft Picks and Prizm. Both have lots of parallels and seem to hold value well thus far. Draft Picks is a notch below Prizm on the totem poll. Prizm is getting into the more expensive end of the game, but still affordable if you can find them in the wild.