Composite Material Export

I needed to export a single "material preview" texture today and realized it can't be done. I never considered that this wouldn't be possible, though I know it's not normal anymore for a game to use one texture. I ended up screenshooting the material preview and managed to get what I needed, but I would perhaps like the ability to do that again as the need arrives.  However, the screenshot work around is fine.

If there is a way to do it and I have overlooked it, please let me know.