The LightWave Assets / Plugins database maintains a list of free and commercial third-party plugins available for LightWave.
Interactively move an object along a line defined by two points
Interactive length and angle measurement tool
Interactively move and snap the selection to points of another object
Powerful tool for creating polygons, 2-point poly chains and splines
Interactively roll and snap the selection to points of another object
CAD plugin for LightWave
Compute the area and volume of selected geometry in Modeler