Photos published (no articles) in various text books, sometimes many in a single publication. For these assignments I was given 1-3 days to produce images of specific subjects. The pay was extraordinarily high, therefore, I rarely turned down an assignment - I was usually contacted when other photographers failed to produce what was needed by the book designer and the situation always commanded a higher than usual pay rate.
Also, industrial photos for a large engineering corporation (annual reports) and hundreds of product photos for a small manufacturing company.
I should note that the demand is for all digital imaging now for this kind of work.