Here's another tutorial from Blendergrid user Mike, covering some interesting orthographic renders: Oblique projections. They are normally used in specific types of technical drawings or stylized maps. There have been some requests to support oblique projections as a new camera type in Blender, but right now you have to use these tricks to get them.
Oblique projections cannot be created simply by the pointing the orthographic camera in the right direction. If you look at the middle and right images in the thumbnail, you'll see that one side of the cube-castle appears as a square, and yet two other sides are still visible. This tutorial explains how to render the three projections on the thumbnail.
This tutorial features Mike Futcher's baby son Odin on backing vocals, and 'Flight of the Bumble Bee' - Rimsky-Korsakoff (v. Rachmaninoff) recorded by pianist Paul Barton.
If you like the way Mike explains Blender, here's a link to his YouTube channel for more Blender tutorials: YOGYOG - YouTube