Is there a "get individual"? I have a grid and a plane which are not parallel. 



I'd like to move (G-key) the selected set of points down so that the value on the z axis of each point after moving is the same as the value on the Z axis at that corresponding point on the plane. The effect might be what one would achieve if one took the "move" tool, the "individual" part of "extrude individual", and the "snap to plane" function. Am I looking for something which does not yet exist?
Well it doesn't exactly exist as a tool but you can achieve this with a vertex group and the shrinkwrap modifier.

So you first take your selection and assign it to a vertex group, then apply a shrinkwrap modifier with the target being the plane below and the shrinkwrap mode being "Project". Then you just need to select the axis you want to project along and the direction on that axis.

After you've done all that you should have your result. You can now apply the modifier and delete the vertex group.