Hey! Thats a cool concept, and I have a very similar plan for more to come. I have plans to make it so in the main menu, you can buy cards to add to the more basic ones. I hope to have 50 base cards with their uncommon counterparts than more then just the 6 i have right now, thanks for your feedback though!
EDIT:
TBH, I have been quite tired from programming so i haven't really had the time to implement a main menu, but now that I see this i will put more attention to it. Thanks!