According to comicbook.com, Amazon may have inadvertently leaked plans for a full-blown Dungeons & DragonsMagic: The Gathering crossover. Earlier today, D&D fans discovered an Amazon listing for a D&D publication titled Guildmaster's Guide to Ravnica. The listing for the book specifically calls it a campaign setting, which would make the book the first full campaign setting publication since Sword Coast Adventurer's Guide. Dungeons & Dragons has been teasing new campaign settings for weeks.