Blue Ability Cards are a type of Ability Card, and you can only have one of it in the game. Blue Ability Cards are usually designed to give a Bakugan a boost in G-Power. While most Blue Ability Cards have G-Power Bonuses right on the left on the card, sometimes this is not the case, usually when the amount of G-Power to receive is dependent on something else. While it is true that some Blue Abilities have higher boosts, this means that that card will most probably have an extra ability, so sometimes, it can be good to just play it safe.