The Art of Diablo Book - Diablo 4 Pages Revealed
Reddit user Exposition_Fairy received their The Art of Diablo book early and posted all pages online!
BlizzCon 2019 Main Hall Campfire Leak
Reddit user gustavoquandt posted an image that appears to relate to Diablo showing chracters around a camp fire. This is rumored to have something to do with the Diablo IV character screen.