Simple

A Plane a x+b y+c z=d

A Sphere x^2+y^2+z^2=1

A squared off sphere x^4+y^4+z^4=1

Three Planes x y z=0

Hyperboloid of 1 sheet x^2-y^2-z^2 =-0.1

Hyperboloid of 2 sheet x^2-y^2-z^2 =+0.1

Ellipsoid a x^2+b y^2+c z^2=1

Parabaloid x-y^2-z^2=0

Saddle Surface x+y^2-z^2=0

Torus