I miss, or cannot find a feture in the collection area, where I can see all those NOT in my deck, would be so much more nice to organize them if there was such, I know I can look at the "Put in deck"/"remove from deck", but thats get complex allready at 15-20 cards... so a filter to see whats not in deck would help alot..
That option is in The Market, and you can also organize them by price, so it will be easier to know which one you can afford or save up for.
Yes they should implement a filter in your collection that tells you which cards you are missing.
Using the market you are depending cards for sale. But if I want a full list of my missing cards and no one is selling one of my missing cards then I will not see that card in the list.