For symmetrical balance I chose Diego Rivera's "Vendedora de Flores" which is almost, but not quite symmetrical. I thought it was a good example of how symmetry was used to show the strength of the flower vendor and the weight of her load.
For asymmetrical balance I chose Andrew Wyeth's "Christine's World". Christine the focal point and is positioned diagonally pointing and the eye follows her gaze to the buildings on the horizon. I've always found this work to be very powerful.
My rebel artist chose Charles Demuth's "I Saw the Figure 5 in Gold" as an example of radial balance though I may be stretching the definition. The line drawing clearly shows the numeral coming from the center and growing. The background also radiates from the center.
For crystallographic balance I chose "Personnages Oiseaux Etoiles" by Joan Miro. I could have picked almost any of his work for an example.
It was interesting for me to go though my portfolio to determine which balance I used in my own pieces. I did create some collages and drawings.
A tree with its root structure for symmetrical balance. Trees are my default image.
Two asymmetrical collages, the first an attempt to use texture and value to create the asymmetrical balance. The second, color and shape.
I drew some mushroom cross sections for crystallographic balance. I stared out trying to do radial and if I crop any single element then I guess I have radial balance. But I started playing around with scale and it became what it is.