Sketching Idea addon is a new tool when you are sculpting. Are you stuck with your sculpt? You have a couple of good ideas in your head, but sculpting those ideas one by one will take too much time and effort. With this addon, you can quickly sketch your ideas and then sculpt the best one. The best thing here is that sketching stroke will vanish from the view according to your camera angle. This feature alone is something you didn't realize how much you need it before you test it the first time.
All future updates are free.
Shortcut for this tool is SHIFT + CRTL + A