1.
Massive database of free models of almost everything you can think of.SketchUp is widely used by architects so you can be sure that any famous building probably will be present.Apart from 3d stuff there are many 2d cutouts like trees and people

2.Non-realistic rendering/Sketchy edges .If you have a 3d model and wish to turn it to something more(or less) artistic you can use the program to transform it in to a rough sketch or a precise drawing.You can keep the existing textures if you wish

Now for the "game" examples that I created for your own viewing pleasure in SketchUp/Photoshop!

