Within NGA, there's a significant body of stuff that "is NGA" that isn't in any of the classical forms. It's taught in every NGA school, and apparently was part of the curriculum in Japan. The forms were meant to be specific training tools, rather than containers of the art.Same here. Not everything was taught in forms. The forms were a catalog of techniques, but the forms didn't have all of the techniques. There was a lot of that I personally taught that weren't in forms. My teachers did the same thing as well. Additional things were taught outside of the forms.
Edit: I'm assuming that the stuff that my teachers taught, but weren't in the forms, were the new things that the teachers added over the years and felt that students should know. Some of it came from other systems, and the teacher always made sure we knew what was Jow Ga and what wasn't.