Pokémon was such a well-known cultural event (it's a card game, it's a marketing gimmick, it's little animals....) that even South Park based an entire episode on it (season 3 episode 10 and of course you should go watch it now free (legally) online).
So perhaps we shouldn't be too surprised to find that the masters of homage at Sony included it in EverQuest II, since they included dozens and dozens of cultural references in the game. As I've pointed out, this kind of behavior is common human behavior and occurs in a lot of games, not just EQII. (Sony makes an appearance in the South Park episode at about 5:30.)