I do agree that the black and blue version is mucho classy.
If the plan is to do only one side, then I might suggest getting rid of the URL and opt for more tag info instead. Thought process: the people who own these tags are already going to be familiar with your website (theoretically, they bought these cards from the store already), so the URL doesn’t serve an immediate function to the user, whereas more information about the tag makes it clearer what each card would be capable of.
Either way, the cards look very nice and I’ll probably be picking up a set 