I know the down B footstool is common knowledge, but do people know that you can make the footstool 'automatic'? You can press jump immediately after starting the down B, and if, at any point during the animation, you are above an opponent, ZSS will do her down B footstool jump in the direction you're holding.
Another way of doing it, is to down B, and then hold tap up during the animation (works even if tap to jump is off, which makes me think it is unintentional), but I think the first method is easier...
I haven't found any reference to it anywhere in this forum, but I'm not sure if that's because it's unknown, or that people don't find it useful.