You mention comic-like - for charts (as opposed to diagrams), XKCD has been a source of inspiration for a more casual style. Here's one example: http://xkcdgra

You mention comic-like - for charts (as opposed to diagrams), XKCD has been a source of inspiration for a more casual style. Here's one example: http://xkcdgraphs.com/ http://xkcdgraphs.com/ (there are plenty of others if you search for them).