In our Electric Spec submission guidelines, we’ve decided not to do as some other ‘zines have done and list story plots that we see a lot. Even so, there are story plots that, at least in my book, are long shots. These include stories about:
-- Robots that turn human or with whom their creator falls in love
-- Vampires, werewolves, or zombies that fit within one or more of the stereotypes of such creatures
-- Someone turning in to a vampire, werewolf, or zombie
-- Someone killing his or her spouse, girlfriend, mother, etc. (Some of these creep me out, but for the wrong reasons).
-- Light speed travel (or cryogenic sleep) has caused the protagonist to return to earth after some sort of space mission to find the world changed
-- Lots of fighting (e.g. sword fighting, space duels, laser battles) and not much else
I would also add that I see very few flash fiction stories (i.e. stories under 1000 words) that make the cut. Why? Good flash fiction is hard to write; you need plot, you need voice, you need character--just like in a longer story. So, the economy of words needs to be incredible. We pay the same for flash as we do for a 7000-word story, so I judge flash with the same (if not more) vigor that I judge longer works. If you want to see my approach to flash fiction (yes, I know, blatant self-promotion) you can check it out here:
http://www.astoundingtales.com/TheFortuneTree.htm.