Cards are coming and they aren't attached to weapons and armor like in classic Ragnarok Online.
They are attached to your character and you can switch between 5 different cards. That means you can use different equipment with the same cards, unlike RO. Different card combinations will give a specefic bonus, like card sets in RO1.
Your character customization is now done via equipments and cards and not manual stat point allocation.
There are three types of grades for each card. Bronze, Silver and Gold. Gold being the best and the rarest. Bronze cards will be fairly common and not to hard to obtain.
You can turn a number of bronze cards into a silver, and a certain number of silver cards in to a gold card.
You can also combine different bronze cards to create a mystery gold card.
There is also a collectors album, and you can try and collect all cards.
Kafra flying service
Seems like there will be a way to move quickly around the world of Ragnarok, besides the mounts.
Check out the Ragnarok dev team having fun with this new Kafra: