I saw this one Gestalt Post-Apocalypse world (w/ Resident Evil, Highschool of the Dead, Day After Tomorrow, Fallout, etc.) and the MC has a system that trades with merchants in other worlds, and those merchants are like, all stupid retarded idiots, like Aqua Konosuba, Danmachi Loki, Yorinobu 2077, Ash Pokemon, Elden Ranni, Hokage Tsunade, etc.