Perhaps if there is a demand for it, we could have a subset group of laboratory cultured microorganisms ranging from various Ascomycetes and Basidiomycetes, to others. I'm sure there are a plenty of neat lab drawings floating around. It'd be cool also to indicate the magnification, so the person can get a grasp of it's relative size within the subset, in addition to the number indicator that Dave pointed out.
They could easily be touched up in Photoshop, or left as is, preference really.
[Fungi aren't as boring as they sound, I have a drawing of a Basidiumhttp://www.botany.hawaii.edu/faculty/wong/Bot201/Basidiomycota/Basidium_Development3b.jpg that imitates Batman ]