Here is a little breakdown of a tool i created called TrackAssist. Based on the core of my StickIt toolset, this tool uses the CameraTracker node to generate relative motion to guide tracking points, in areas where the 2D tracker would fail. It has the option to triangulate or a full frame median. One of the major advantages is that you can use this tool with roto or keying, and that it can track areas that are off-frame.
Another tool in this series is RotoAssist, that like this tool works a bit like a planar tracker, that unlike the Nuke Planar Tracker supports masksing and keying.
[Footage from a beauty project i helped work on, check out dolcerocca.com/ for the full shot]