GG has created a new plugin, called Tracer.  It creates an outline (i.e. traces) around an object after a few points are designated.  You can then "fill" the alpha channel with its mask, like with a gradient or another object on another track.  Although it works well for still images or objects that stay in the same place on a video like a logo, you can also add keyframes.

There is a quick demo at:   https://streamable.com/o8bse

In the video, you can not see that instead of using the "New" button in the controls menu, I use the right mouse button.