You can pick any color pair here and come out with a playable aggressive deck, and you can even splash into a third color if you'd like
Bedrock Tortoise Bedrock Tortoise defends your creatures as well as making your high-toughness creatures threats in combat
Some control decks may play a copy of Mystic Sanctuary so thats something to always consider alongside Uro or the odd Snapcaster Although we dont see these decks too often these days, for historic reference: Reanimator: Reanimation targets, Faithless Looting Hogaak: Bridge from Below, Hogaak, Arisen Necropolis, Vengevine, Bloodghast, Gravecrawler, Cabal Therapy Madness: Vengevine, Faithless Looting, Anger NicFit: Cabal Therapy however, really no specific card other than Academy Rector in NixFit builds
Distemper of the Blood
Similarly, booster packs of cards are constructed in a way to feature four different rarities of cards mythic (one in every eight boosters), rare (1 per booster), uncommon (3 per booster) and common (10 per booster)