Ralph Lengler and Martin Eppler show a variety of many different visualization methods, arranged as a periodic table. Six categories differentiate the various entries by visualization type: Data, Information, Concept, Strategy, Metaphor, and Compound: http://www.visual-literacy.org/periodic_table/periodic_table.html (version 1.5; no date).
Make sure you mouse over the “elements” to see samples and learn more! Great idea!
