Welcome back, Black Lotus. Magic: The Gathering’s single most famous card has returned to the top of the expensive cardboard pile thanks to a private auction where someone paid a soul-squeezing $3 million for a copy considered to be in perfect condition. The news comes from CGC Cards, a grading company that examined the Black Lotus in a crossover submission from Adam Cai of valuables sourcing outfit Pristine Collectibles. Cai’s seven-figure transaction with an online collector who goes by...