Agathe Hi! What card is best for you depends on the country you're living in. For example, the Maestro card is best if you live in the Netherlands or Belgium, because it's the most accepted card in these countries. In all other countries, it's often best to use the Mastercard.
You'll often see these logo's on payment terminals:
They indicate what type of card is being accepted. If only the Mastercard logo is shown, a Maestro card will probably not work, and vice versa. If you already have a bank card from another bank in your country, you can take a look at your card. It'll probably show one of the two logo's (or it might show the VISA logo).
The 3% ZeroFX refers to payments in a different currency. At other banks, you often have to pay around 3% for converting a foreign currency to the currency of your bank account. At bunq, this fee is only 0,5%.