Whether a part of control, aggro, tempo, or combo decks, Brainstorm was an absolutely defining force in Vintage until its eventual restriction, and to this day, is clearly way, way over the line for Legacy, except that it just gets a pass, because we want it
I say some because Sickening Dreams isnt necessarily good if you aim to cast your creatures with it since they resolve first
While it's not apparently company-wide policy, depending on where someone lives, some stores have reportedly just sold the Pokemon cards instead of a plethora of Happy Meals
Specific print Physical Token Cards with artworks associated to specific Monster Tokens, but none of their properties (including name)
You can even configure the mod to slow down if you find a particularly rare card
There are some rules for building your very own Pokmon deck