Upload the tracking number directly into the marketplace so it is stored for both buyer and seller. Automatically email the buyer with the tracking number too.

This makes it easier for both users

I have some cards from Halo of Awakening set that I’d like to add but there isn’t even a Battle Spirits or Battle Spirits Saga category option.

Being able to prioritize which games, systems, accessories to acquire first based on desirability would greatly improve efficiency of purchasing efforts.

I have gotten to the point where I have amassed a good collection. I think it would be super cool for a weekend activity to have some sort of randomizer to choose a game from the collection to play. Also, to have a filter to filter out consoles or only include a select few. Not only to filter out consoles, but also features. Such as games that include multiplayer, or specific genre of game a person is in the mood to play. 

The report functionality doesn’t work for reporting Heritage sales. I’ve found multiple instances were Heritage sales were incorrectly categorized, under the wrong game variant, etc. with no way of reporting it.

When a user enters a eBay sale, there should either be an option to input the condition or when the data is scraped the condition from the listing should be utilized. This can be utilized for further analysis or even deciphering how one’s own game compares.

Please add support for foreign coins too

Sort a collection page by issue number or card number.  This would be similar to sort option available on search and browse set pages.

Make a database of action figures and track their values like you do for games, cards, and comics.

Watara supervision was a failed gameboy competitor with over 60 games, three hardware revisions and released in multiple regions, including US, germany, UK, and some asian countries. It is currently not possible to add either the system nor the games properly.