An option to render with cel shading (e.g. a sketched or "toon" look).
Value: presenting cel shaded designs is very useful to subtly communicate that a concept is a work in progress. It can also yield very clear models that are easy to understand.
I usually do this by exporting to Cinema 4D (which has this feature).
Recently I have been able to almost reproduce cel shading via a bug: I have the "Visual Styles"-plugin installed, which gives you the option to change the visual style of the model while in the rendering workspace (e.g., change to wireframe). When you change visual style, the shading turns flat, with various degrees of white and grey, see screenshot (e.g. cel shading). However, the lines sort of break when you export the image via "capture image..." if you don't use the wireframe option. And, the image is aliased a lot when coming out.