In addition to the sideboard, I would like a deck wishlist. It is a place where I can put all the cards I am considering adding to the deck or considering purchasing to add to this deck. Right now, I use another "invalid deck" to store my card ideas, but I want to attach the list of cards I am considering to the deck itself. I don't want a limit on these cards, and it should be easy to swap them in and out as I test and craft my deck. As of now, putting unowned cards or too many cards in the sideboard invalidates the deck. But putting too many cards or unowned cards in the wishlist shouldn't invalidate the deck.