this is a newer one you may not find on many cliche lists, but it seems any bit of obscure information can be found on the monster in three seconds using the internet. the information is always exactly what's needed and the characters believe in it without a second thought. thank gawd for google, eh?
maybe it's just my computer, but 90% of what i find actually useful research is contained in a book for sale. were i to look up how to kill that one particular brand of werewolf, that would only be found in an ebay or amazon link for the low, low price of six bucks. and no porn sites ever pop up, either. (anyone who knows how to permanently block vizitus.com, please let me know!) (okay, this more of a movie cliche....)
in books, the virgin daughter is incredibly hot who at most manages to keep her virginity intact by providing other services to her boyfriend, who she had to leave behind when her family moves to a new burg, almost always some rural area. confronted by the evil, she suddenly can't control her hormones. well, she can, but barely. sometimes. sometimes the evil takes her virginity. all this to illustrate that sex is evil and punishable by death. oh, but, bj's are okay.

what a nice message, eh? lol.
the surviving heroine from the first movie is now a side-character in the sequel, invariably having gone through an extensive psychiatrict process, sometimes still entombed within the sanitarium.
*if* there's a single survivor, it's always a female. men are too stupid to live, apparently. (personally, i have no biases like this: i kill every character by the end just to be fair.)
being mindless means you are criminally unsane. intelligence, i guess, promotes good. too much intelligence, though, and you're too smart to be good. another great message to send out: if you're dumb, you're a killing machine: if you're a genius, you're out to kill millions in one fell swoop *or* fall into the serial murderer category. either way, each extreme means you have a criminal mind. average people *can't* be killers.
factory workers are evil in a special way. have to have some skillz like a machinist, though. popping rivets into sheet metal just isn't enough to drive people off the deep end. you need to be able to fabricate your own weapon, preferably something to replace the hand you lost.