Gen 1 and 2 Team Rocket are still the best Pokemon villains. Legitimately cruel and evil and for completely realistic, rational reasons. They're just a organised crime syndicate that cares about profit over any sense of morality or ethics. No stupid major world ending plots or naive lofty idealistic ideals gone wrong, just a bunch of lumpen psychopaths who want some money. Something about that makes them and the shit they pulled way more memorable than anyone else.