This theme is based on general graveyard interaction.

Related Themes:
discard (moving cards from hand to graveyard)
sacrifice (intentionally moving cards from your field to your graveyard)
wheels (mass discard and card draw)
aristocrats (creature-specific sacrifice)
dredge (cards with the keyword "dredge")
self-mill (moving cards from the top of your library to your graveyard)
mill (moving cards from the top of their library to their graveyard)