You want to constantly be attacking, especially early in the game if you cast Dion after a few turns before your opponents can set up flyers
While its not quite strong enough to push into CEdh, Edgar makes for a strong commander
Key Cards Alania, Divergent Storm The commander of the deck, Alania, Divergent Storm is what enables it
You know you'll get it out on turn 3-4 and you just need to hit a way to mill or search for something to put in your yard early, and then you can move into midgame with a big threat on the table, and the ability to get it back without jacking up your commander tax repeatedly
In more recent times, cards like Kataki, War's Wage and Ancient Grudge have further suppressed Affinity's ability to perform at the highest levels
While not quite free, possibly the most abusive card to cast off a big damage Rakdos turn is Maga, Traitor to Mortals