I have a mill deck that uses Sphinx's Tutelage among other things. I'd like to find a card that could combo with it by allowing me to draw when a card is put in an opponent's graveyard. I'm not sure such a card exists.
Compost would be perfect, except it only works with black cards. There should also be a way to get out of the loop so I don't mill myself.
Modern-legal would be best but this is more about curiosity so it's not super important.