Cardfinder Booster Pack

To enhance a Cardfinder card deck, one can acquire booster packs with 3 (?) random cards in them. Those are sold by specific merchants or can be found elsewere.

When opening such a booster pack, the exact cards are determined like this:
First roll 1d100 to determine its rarity. Then roll again for the exact card to get within this rarity, where all cards within the same rarity have the exact same chance to drop. Repeat this until all cards have been determined.