This is reminiscent of the signatures seen on the old World Champ decks back in the day, but scaled up for the modern era
Back way when, Wizards didn't really make sure that there were ENOUGH playable limited cards in the common slots for sets (no one was playing much limited before the inception of the Pro Tour, around the release of Ice Age ), so horribly unplayable cards like Snowfall and Balduvian Shaman glutted the common slots of packs - and commons are where most of the meat of your limited cardpool comes from
Rakdos is a bit different in that he can be a one-sided board wipe, but there arent that many other Devils, Demons, or Imps worth playing, and hes risky to play anyway since you could end up wiping your board and not affecting your opponent at all, so he never really took off
This Golgari cards a mana generator, graveyard hate, direct damage and lifegain all on a body that can hit the field turn one
In addition on cast, we mill five cards and return a creature from our graveyard to the battlefield