Gimp Script Fu Layer Effects -

Adds highlights and shadows to edges to create a 3D effect. It is widely considered the most useful tool in the set for creating glass or metal textures.

Creates a shadow behind or inside an object to add depth and elevation. gimp script fu layer effects

Adds a luminous "neon" halo around or inside the perimeter of an object. Adds highlights and shadows to edges to create a 3D effect