There are a lot of discard cards, artifacts that combo with them, and creatures that would be good in a deck. You can use some dark rituals, some mana producing artifacts (lotus petal, mox) and you have a discard deck. Usually discard deck isn’t junk. It’s most black cards and some of red or green cards.

Casino Discards

A high quality, casino-style 6 deck discard holder is made of clear acrylic with a black base. It is perfect for discarding cards after every game so that they don’t get in the mix when a new hand is dealt. This discard holder can be used for any card game.