If you want to find some good examples of architectural visualization made with Blender, there are some websites that you can visit; most of them are related to some external rendering engine that can be integrated with Blender. But their communities of artists create great examples of what Blender can do for visualization.
For this book, we chose to use YafaRay, which is the external renderer that best integrates with Blender. But this is not the only render engine used to create realistic images with Blender 3D. We could use other great external renderers as well: