Utility function for introductory microeconomics What are the utility functions standardly used in introductory microeconomics courses. My own list would include

Perfect substitutes: $U(x,y) = ax+by$
Perfect complements: $U(x,y) = \min(ax,by)$
Cobb Douglas: $x^\alpha y^{1-\alpha}$
Quasi-linear: $x + y^\alpha$
CES: $U(x,y) = (x^\rho+y^\rho)^{1/\rho}$

Anyone else that would be typically included?
EDIT:
To be more specific I am primarily interested in different types of preferences not positive monotone transformations of the above specifications.
One that was not mentioned in question is the quadratic utility (aka preference for extremes):
$$U(x,y) = x^2+ y^2$$
This one is less common but still used in micro courses.