I was working on an animation in Flash the other day. Traditional frame-based animation in Flash is not something I normally do. I was starting to get irritated with having to constantly use the mouse to advance to the next frame so I started looking for a short cut. After looking through the menus and the list of shortcuts you can redefine, I couldn't find anything. I posted to a group of Flash users and within minutes I had two replies... you use the comma and period keys to go to the previous and next frames, respectively. After learning that, I had a vague memory of going through a Flash 2 or 3 tutorial and learning that, could they have been there since v2?
Now let's see if I can help anyone else out with a really obscure key. I've been doing a lot of drawing in Flash recently and I don't know what I'd do without knowledge of the "G" key. When drawing, it is very useful to have snapping on so existing points can be easily connected, aligned, or merged by snapping them together. But often snapping is a problem when you're trying to move to a specific spot. Well if you press and hold the "G" while moving the point snapping will be temporarily disabled. I can say enough how useful this has been. I have to credit the book Illustrating with Macromedia Flash Professional 8 for showing me the light (which I first mentioned here).