The other day I was thinking about the low-poly flat normals aesthetic that seems popular at the moment. What about low resolution 3d? The pixel look, but for 3d graphics, as you would have seen in the SuperFX (e.g. Star Fox on the SNES) and early 90s 3d games.
Mostly displays don't support resolutions below 640x480 anymore, but this doesn't have to be a limitation. Using the Render Texture feature in Unity 5 you can achieve custom resolutions, aspect ratios, and dynamic resolutions.