úmëa ér uilë - Evil still lives?

[Sharkû]

There is no evidence whatsoever that more Balrogs survived the Fall of Angband. Tolkien states in a letter something to the effect that 'here we find one that one has survivied the Fall and hidden', implying he was the only one to do so. Implied or not, we know of no others.

Personally, I have also argued in the past that there were no more Morgothian dragons after the death of Smaug.
Of course Shelob might still be around...

What we know of the evil in the 4th Age is that it mainly comes from the inside, from Man's dissatisfaction with good, resulting in youths playing orcs, secret cults etc.