Six mana is a lot to nab a creature that the Crystal has exiled, but there are few times where doing so will be a bad thing
Charizard 25/185 - Vivid Voltage The Pokmon Company Pokmon Stage 2 - Evolves from Charmeleon 170 HP Once during your turn, you may look at the top 3 cards of your deck and put 1 of them into your hand
However, you won't even be casting it unless you hit its threshold cost (seven or more cards in the graveyard)
Later sets have used Food tokens in a larger way, pushing even more in this direction
if youre of a certain age, you remember the reign of the Beanie Babies, or the vintage comic books, or hell, the baseball card surge in the 80s and 90s
Against Dredge, those cards are Stinkweed Imp and Conflagrate