Ragnarok Online - European Version had Steam trading card support added on December 3, 2013. There are 8 cards in the series. Because Ragnarok Online - European Version is a Free to Play Game, cards are earned by purchasing in-game content (approximately $9 USD per card drop).
This version of Ragnarok Online is only playable in Europe. The alternate version of the game, Ragnarok Online, has a different set of trading cards. Though non-Europeans can't play this version of the game, they can collect the cards (via trading or the Steam marketplace) and craft the badges.