Electric Pokmon often have lightning bolts or electricity coming off of them, while poison Pokmon are often surrounded by clouds or look slimy
(By the way: The Rise of Sozins color identity is black, even if the reminder text on Fire Lord Sozin shows
As you can see, the Expanded format has access to far more powerful cards, which is great because if you want to mix things up, you can learn both Standard and Expanded formats
In this context, an error pack is seen to be a booster pack with cards that are not packed as intended
Still, once your opponents see it in action, they'll see the potential problems it can cause very quickly
Giving any reasonable boardstate myriad across all your creatures is an excellent value play or threatens tons of damage, sometimes both