Outline

Add an outline on all objects of the layer having the effect. 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.

Set the Thickness and Color of the outline to your liking. If a thick outline looks cut off at the edges of an object, increase the Padding property so the effect has enough room to be drawn.

Reference

All effects are listed in the effects reference page.