God rays effect
Cast rays of light from the top of the screen. This won't work well if shown on top of the background color of the scene. Be sure to use an object acting as a background or a floor.

The rays can be parallel (like distant sunlight coming from an angle) or radiate from a chosen center point (like a nearby light source), and their tint can be adjusted. Set the animation speed above zero to make the rays gently shimmer and drift over time, which gives a much more atmospheric, living result than a static beam.
This is a 2D-only effect. It's often used as a layer effect on a background or lighting layer to add mood to a scene.
Reference
All effects are listed in the effects reference page.