Conic Section but in 3 dimensions.
Ellipsoid
a2x2+b2y2+c2z2=1
Paraboloid
Elliptic Paraboloid
cz=a2x2+b2y2
Hyperbolic Paraboloid
cz=a2x2−b2y2
Cone
c2z2=a2x2+b2y2
Hyperboloid
Hyperboloid of One Sheet
a2x2+b2y2−c2z2=1
Hyperboloid of Two Sheets
−a2x2−b2y2+c2z2=1