Unfortunately, I don't think there is any stock art which would cover all of these NPCs. I've received compliments on my choice of art, so I'm glad I did what I did. All that said, I WILL be posting the printer-friendly version of this document (contains no artwork) to DMsguild, but won't be charging anything for it; I want it to be as accessible to many people as possible.
This is quite useful. Thanks to my monster manual recently exploding, I was going to hole punch and bind it, and add some pages of new content. This is exactly the sort of thing I would print and bind alongside wizard's official content and feel the richer for having.