Collectible card games are fueled by speculation and chance: Unopened booster packs can have shockingly high values simply because we don't know what's in them. A single sealed Pokémon 1st edition booster pack is worth upwards of $2,000 because until it's opened, we can't be certain it doesn't hold a Charizard that could buy you a new house. This month, however, has brought upheaval for investors who've built portfolios on the Black Lotus potential of their sealed Magic: The Gathering slates,...