Since the graveyard is often like a second hand for many decks in Commander, denying your opponents access to it puts you at a distinct advantage
One of the better options for a self-discard deck in blue and red is Rielle, the Everwise
Preservation: The durable slab protects your card from damage, dust, and UV light
Green really does have plot armor in Commander, huh
That standard version can be bought for just a few pennies, so if youre more interested in this cards ability which allows you to add a Dressrosa card from the top of your deck to your hand, at a cost of two DON
If your opponent runs out of cards in their deck, and therefore cant draw a card at the beginning of their turn, you win