I saw a post of bread/toast art on some Pixiv account, but I can't find a link back to it. The only details I remember are ones I can't search here by, and my browser history's very short, apparently.
Almy said: I wonder if they weren't all by the same artist?
They aren't by the same artists. In the self-uploading artist website Pixiv (think Japanese version of Deviantart) there was a little 'pool' of these type of creating art on top of coffee using stencils and that chocolate powder. Therefore, everyone pitched in their own art of a particular character, creating dupes and a change in the degree of quality.