Drop shadow effect
Add a drop shadow under your object's visible on the layer.

The shadow is positioned with the distance (how far it is offset) and rotation (the direction it is offset towards, in degrees). Its softness is set by blur, its transparency by alpha, and you can pick the color of the shadow to match your art style.
Enable shadow only to hide the original image and keep just the shadow. This is useful, for example, to render a separate ground shadow that you can offset and squash independently from the object casting it.
Note
This effect only works on 2D layers and objects.
Reference
All effects are listed in the effects reference page.