Nutjob.
Invariably prefaced with either left wing, or right wing, to denote any person who isn't you.
Wrong 'un.
Anyone who may well have less than admirable motives regarding sexual advances to those below the age of consent.
Added To The 'Phile.
Meaning that the actions of a wrong 'un, (see above), have been noticed and recorded by the rest of the forum.
Ned Flanders.
One of the moral arbiters of Bluemoon who thinks that the end of the world is nigh if someone swears.
Curtain Twitcher.
See the above.
Do Gooder.
Weird one this - ostensibly someone who actually gives a shit about his fellow man, but misappropriated by the right as a derogatory term, possibly because they don't understand it.
Dullard or Simpleton.
Any forumite who I have argued with, which means everyone.