With very DLC and major event, Gearbox changes the weapons that are viable for higher mayhem levels. Currently some of the best are: Yellow Cake, that drops from the bosses in Villa Ultraviollet. The recursion, that drops from General Traunt. (this one only works on builds that are specialized for it) Kaoson, that drops from Captain Traunt SandHawk, that drops from Katagawa jr. The anarchy, is a world drop in the 2nd DLC Hyperfocus XZ41, world drop Krakatoa, world drop The monarch, drops from Killavolt The Custman, world drop The Hellshock, drops from Gigamind The lob, drops from Graveward Currently there is an event called Farm the World. Each week one planet gets increased drops. This week it's on Eden-6.