I don’t consider Darkseid to be a non Superman villain, because I consider Kirby’s 4th World to be a Superman Spin-off series.
Vandal Savage: I feel he’s more respected outside of comics then in them.
Killer Frost: 2nd favorite ice themed villain and she stands out because her ability is an actual power rather than tech.
Fatal Five: my favorite supervillain team. In my opinion they are the most powerful villain team in relation to size to. Mano and persuader can one hit most heroes. Tharok Is a genius and EE and Valadis are world beaters