I don't usually post warnings for my stories, but readers should note that I've got a nasty streak a mile wide so there are elements of horror and torture in many of my stories. In fact, anyone who gets upset at the mention of bloodshed or other horrors in my stories ought to remember it's very common in the canon of the fandoms I work in.
Now my use of these elements is by no means gratuitous, but they are often used. Having said that, none of my stories would be rated any higher than R (16), so it's all work safe. I don't usually have swearing in my stories - when it does appear it's mild or just alluded to.
What I don't do is write sexual content because I find it voyeuristic to do so, and that squicks with me. When I do write romance, it's with male/female pairings since that's how I roll.
The bulk of my stories are Tolkien-based angst and psychological dramas, which typically involves someone doing something really stupid, then paying for it for the rest of the story. In my Maiar series, I have feuds that span millennia - it's all Sauron's fault.
Sometimes I'll do comedy or fluff, but angst is my fanfic bread and butter.