Glorfindel. He isn’t in the movies and doesn’t have an all to big role in the LotR books but he’s there. Reasons: Slayed a Balrog singlehandedly (very successfully at that, more so than Gandalf and from the descriptions I would say he did it better than Ecthelion, too, from what I know of at least), Lord of Gondolin - later in Rivendell, reincarnated from death, sent back to Middle-Earth by the Valar and being the only one to ever go there after the rebellion, the Nazgûl rather flees from him than fighting him, when re-embodied he was granted powers that nearly equals that of the Istari, like really, really, old. I read that “even he couldn’t stand alone against all the Nazgûl on horse.” So, as long as the Nazgûl aren’t on horseback then he can defeat them (depend on where I have read that, don’t know if it’s true). The Witch King chose time flee instead of fighting him at some battle I never can remember the name of where he also made the prophesy that the Witch King wouldn’t fall by the hand of any Man (which Eowyn later fulfilled). Well, let’s say that he’s one of a kind :))
