The LightWave Assets / Plugins database maintains a list of free and commercial third-party plugins available for LightWave.
Channel Modifier that gets its data from the Global Ambient Intensity
Analyzes an HDR image and creates a light rig that matches
The LightForge Render Network for LightWave3D
Allows you to easily setup multiple render passes
A collection of new light types
Image based lighting preset and configuration system