In NFL Shuffle, all of the cards are ranked 1 through 6, with 1 being the weakest of the cards that you can get, and 6, of course, being the strongest grade that you can get. The higher the grade, the rarer the cards are. You’ll end up with a whole army of grade 1 and 2 cards, but the chances of finding a grade 5 or 6 card are VERY slim. Nevertheless, read on to find out how to get more high grade cards!
The most obvious way to get more of the high grade cards is to get more and more silver and gold card packs. You can get plenty of these by simply playing a lot of season and versus games (thereby using up all of your season and versus energy), and earning silver balls and gold balls (which appear randomly). The more of the silver and gold balls you get, the more chances that you get a silver or gold card pack. Both the silver and gold card packs have a slim chance of earning you high grade cards, although gold ones have a higher chance.
You can get gold either by completing goals or by earning it from silver and gold balls, and then once you get 250 gold you can use it to buy a premium card pack. A premium card pack will earn you a guaranteed grade 4 or higher card, making this the single best way to get those rare cards.
In addition, every day that you log into the game, you will get a new card, and the more days go by, the more rare the cards will be that you get. If you log in every day until day 5, you will get a grade 6 card. Every day before that you’ll still earn high grade cards.
And finally, when there are limited time events such as the Gridiron event, play them as often as possible. These events usually have better rewards than the main portions of the game, which, of course, includes high grade cards that you can win and then add to your team.