It would be cool to include either on the home page or a separate section (like the price it and no more secrets games) a “Game of the Week” or something like that. Possibly even with a little bio on why (an announcement of a sequel, getting taken off the Steam marketplace, etc).

Please increase the size of the pictures of the cards. Have an option to change the size of them as well. Please see Pokedata's website and picture for reference.

I prefer Pricecharting's website over anything, but this feature alone would make it 100000x better.

Currently there is only BGS 10, which is different from BGS Black Label. As such, the value of the card in the market is only compared against BGS 10, which is significantly below Black Label, thus giving an inaccurate value of my collection. 

This seems like a basic piece of info to include in the exported csv of a collection, not to mention all the other missing fields that are present when adding to yor collection but not included in the export. At first I thought it was paywalled but I saw no mention of that being included in the tier above premium.

Add "# in Wishlist" data point to the Prices API. This data point is found in the "Item Demand Report"

This is a good data point to look at along side price data to gauge market demand... if item is hot then price could be slightly higher than market rate.

Ability to scan and catalog non-sports cards (Marvel etc.) via reverse image search (more accurate) like hipcomic.com does with comic book covers. 

I have many items that say the value is 0, however there is many sold listings on ebay. A way to link them to the item would be nice so we can get a more accurate value to our collections.