I don't remember if I was using query tracker at the time, but I had some "false positives" when I searched for agents who rep horror. They'd come up in the search, but when I read deeper into what they represent and what they'd like to see, oftentimes horror wasn't on their list. Just something to watch for.
Some places don't have it on their list of things they are interested in, but say it's a firm with several agents... one of the agents might be interested in seeing horror novels. Just because it isn't on their list of interests doesn't mean that they don't want to see it specifically. It's just not what the majority of the agents that work there are actively seeking.
Michael Carr, who was recently taking questions in the agent section, loves horror, but on the website of the agency he works for, horror isn't on the list. I asked why the agency wasn't looking at horror. Mr. Carr said he loved horror, he betas for horror writers, his first sale was horror, so he was definitely interested in horror. But it wasn't on the website.
Sometimes, a short email to ask if any of their agents are willing to see a horror novel (even if horror is not listed among their interests) will get unexpected results. And I think a short note asking a question like that will get farther than blind querying agents - the staff would likely much rather answer a quick question than have yet another query letter in the general slush pile. Unless it says somewhere on the webpage that they are specifically NOT interested in horror, I'd check. You never know what you might be overlooking.
And if I'm not mistaken, our very own dgrintalis is repped by an agent whose website doesn't have horror listed among the interests. Dammit, now I have to go look to make sure.
