Visual tools
Visual tool vary greatly and can be any number of things. I have used Photoshop or Pixlr to edit photos that you have taken yourself, or to access creative commons licensed items that others have made.
This is a mind map that I made using SpiderScribe, which can be a really powerful tool when educating. For me it really helps me to see the big picture, and how individual elements interconnect. This mind map is particularly big, so you can see a more detailed version (which will let you move around and zoom in) here.