8. Q
Quite possible the best antagonists from The Next Generation, and I'm including the Borg in that statement. I think the only reason why he didn't appear in a film was because it would take too much to explain him to viewers who didn't see the television show. Everyone can pretty much understand zombie cyborgs who want to assimilate people plus you can explain the Borg by showing people rather than requiring one of the main characters to explain it by saying "Oh it's Q, he's an omnipotent being that likes to meddle with humans". But you have the time to show him properly in a television series. Plus, he's never appeared in a bad episode. Sure there's the one with the pig like aliens in Napoleonic costumes that was a bit weird. But they killed Wesley Crusher, so even that episode gets a free pass. Having Q in an episode of Star Trek is saying that it'll be average at worse, and usually good. Besides, if you run out of other ideas you can always have the lead character punch him. Q is effectively Loki in Star Trek. Q is ageless. Ish. He has the ability to change his own appearance at a whim. He also now has a son. But John de Lancie is also older. So Q would simply appear older. But how do we explain it? Why would we? It's Q. He doesn't need to explain himself to anyone. Besides John de Lancie is brilliant as an actor and any new series would be lucky to have him.