2D line 2D angle 3D line 3D angle
These are used primarily used for measurement. However, you can HACK them around as line pointer tool.
2D vs 3D
2D tools will NOT MOVE when you change your perspective (just like dust on camera?). 3D tools will move as you change your perspective (eg. just like dust on the visible object, its visibility will depend on your perspective).
Line tools can be used to point. However, you cannot eliminate the DASH at the end! Which can be a problem.
If you start at point A and end at point B then point back to paint A and forms a 0 degree angle and allows to use angle measurement as a line pointer instead! Just make sure you delete the angel display at the end.