I found a list of seven a long time ago but lost the reference, they are:
1. Polygon (includes the Circle)
2. Sphere (least surface for given volume)
3. Spiral (6% more growth along one side)
4. Helix (3D Spiral)
5. Vortex (Double Helix)
6. Meander (River Flow, etc)
7. Branches (4 types: Explosion, … Read more