Misanthropes

If these baddies had succeeded, humanity would’ve gone the way of the non-avian dinosaurs.

Misanthropes are characters who hate or dislike humans, they harbor a serious hatred for humanity (or other sapient species their respective settings) and may even be Genocidal in those regards. Misanthropy can lead to villains committing terrible crimes as they no longer have compassion towards their fellow people and in fact despise them.

Many human villains themselves (such as primate humans, cavemen, or modern-day humans) may also be misanthropic or self-hating humans, as they view their species as mentally stupid, inferior, irredeemably flawed, or worthless. This could also include the Undead (Noncorporeals, Zombies, Vampires, etc.) that are disdainful for the living.

Non-humans (Aliens, Robots, Animals, Plants, Humanoids, Monsters, etc.) may also be misanthropic as they view humans as stupid, inferior, irredeemably flawed, worthless or oppressive. However, it should be noted that not all are necessarily misanthropic.

Good examples are Ultron, AM, Godzilla, Joker, Shere Khan, Megatron, Daleks, Bela, Cthulhu and the Drej.