i d like to play also a mini game, maybe finding around the world some little creatures minions that could be called "cardist" or something else, that you can find around the world, that you can you only when you find another NPC with a minion.
Every cardist must be trained making it play with other npc who have this minions,
winning you can get some valuable info about secrets, hidden treasures, money or other minions to find, always stronger.
The game that you can play must be something not too elaborate ( or yes, dipend how much time you can use to delvelop the idea ). dunno like perudo, black jack, backgammon, or similar. or something totally different. but depend on you how much time you have to develop the idea and if you like it.