18. The Borg
The Borg are the most unique villain in all of Star Trek. A cybernetic single entity comprised of many billions of captured and assimilated individuals and species.
They are a relentless force, swarming across the galaxy like a disease. Effortlessly decimating entire cultures, snuffing out the fragile light of their individuality and repurposing them as part of the one collective Borg mind.
The Borg take Star Trek into the realms of horror, playing on fears of torture and mutilation and of the loss of the mind to a domineering force. It’s body horror, it’s phycological horror, it’s about as terrifying as you can get for a primetime family show.
The Borg are so compelling because they are so other, it’s not another humanoid species that you don’t see eye to eye with but can never the less understand and relate to, like the Romulans or the Klingons. The Borg are something else entirely. They’re not malevolent, they’re not politically or economically motivated. They just are. They’re the most alien aliens in Star Trek. And for that, we love them.