What you end up doing is drawing the card you need more often than you would otherwise
My examples here are a playtest card that is not for Constructed play, a Commander format-specific card, and a superpowerful card translated from Arena's Alchemy to paper
While you could consider any card with the Rakdos watermark as a Rakdos card or even some mono-colored cards that have mechanics that fit Rakdos decks perfectly, for this ranking I talk about cards that are specifically both black and red in color identity
The other day, for example, my opponent played the above-pictured Vicious Battlerager on an otherwise empty board
Mox Amber is a lost relic from Dominaria that never had enough Standard support to warrant inclusion
If youre guaranteed to draw cards on your turn then youll be able to have a huge amount of control over what youre picking up or just set up your next few turns with the cards you need, when you need them