That was originally the point of the site actually, haha. Collecting all the items, but more importantly, all the items in a complete set. It was recently expanded on by adding that little counter below each item's name. There was also going to be "badges" for getting all items in a certain set.
I tossed that idea out, in replacement of "Achievements" which will show up in your profile above badges, but also be worth an extremely large portion of points (for leaderboard rankings). The achievement will show a unique image from that game (without showing the items specifically) and announce that you achieved "The Legend of Zelda Collector" for example. This is not currently implemented fully, but it's on that ever-growing list
. Achievement will work on a one-time-thing basis, so after you collect the items, and get the achievement - it's there permanently, you can sell them, or keep them, whatever you wish.
Also planned is other, non-item specific achievements like "10,000 gold collected" or "500 games played". I'm open to input and suggestions, like everything on the site