This is going to sound really nitpicky, but collectors are. While I do not collect MTG (I strictly play) I do collect other things, so I understand the mentality.

Is there a way to customize the card listings, or create a card or sub-card listing that is not in the database?

The reason I ask, is because the tokens can have several different backs. To a collector, this is important as he tries to determine how many different backs there are. In some collectible sets (notably sports cards such as the T-106 cigarette cards - you've seen or heard of the ultra famous Honus Wagner thats worth millions) some cards carry a premium, because the backs are rare. While I doubt that would ever be the case for MTG tokens, for collectors, it's a nice touch, and a sign of their obsession.

Perhaps a way to share the back with other collectors? This would need some sort of verification, however.

Thanks to the developer for this invaluable resource.