Not only is the Power Nine mostly artifacts, but some of the most broken cards I can think of are artifacts: Skullclamp, Umezawa's Jitte, and Smuggler's Copter all demonstrate the power of the card type before I even scratch the surface of fast mana like Mana Crypt and Sol Ring
Recursion Since we are in the colors of recursion, let's push that theme
The Math: These sets established the gold standard: 4 to 5 Legendaries per box
Little John Resourceful Outlaw This Little John character could be a really powerful ally to the currently popular Tiana Aggro Deck that leverages a collection of bodyguards to defend high questing characters
75% Of hands are public information, and deciding what to (and what not to) respond to becomes a whole lot more fun (or frustrating, depending on who you ask)
Kaalia of the Vast leads this deck as a red, white, and black commander, one that unites Angels, Demons, and Dragons together under one banner