Extract a 2D shadow pass from 3D for 2d manipulation. Or project soft shadows back into a 3D scene for use with the OpenGL renderer.
Create true 3d light effects with rays. Separate light effects from geometry in the 3d and create 2d masks from 3d materials.
Light a 3D scene in DaVinci Resolve & Fusion and use advanced 2D tricks for volumetric lights and light wraps.