Will there be consequences after opening tarot cards?

You know tarot cards are printed first, and then they become tarot cards.

So relax, it's just a box of cards. If you don't use it, it's just beautifully printed paper.

Tarot cards themselves do not have any magic and negative effects, so they will not pose any "threat" to you at all. Your worries and anxieties are superfluous and unnecessary!