Quest items?

I have some quest items that are worth 0 gold, what is the point of picking them up or even having them?

if they are 'markers' of any king there is no reason...they simply mark the path.

otherwise they are items you were/are supposed to bring to someone. GuildWars doesn't always remove them from your inventory when you are finished with the quest. If you are done with the quest that requires the item you can trash it

Or you can try to scam a newbie and sell 'em, like many other try to do.

To answer your question, they serve no purpose really. They only exist to temporarily occupy a spot in an already limited inventory.