@therealnoahgibb said in Can we add an inventory filter to view all duplicates?:
You can do this on the desktop/mobile browser version. From community market, Go to market filter, select show quantity owned and show inventory only. All the cards you have duplicates of will have a x(and then the quantity owned) on the card. Still have to go through your inventory but it is way quicker than going through manually on the game.
I did not know about this thanks for sharing I'm going to do this right now