The most facial expression variations for minifig heads?

[General Magma]

I'm planning to get back into making LEGO stopmotion videos, but one thing I would find really useful is finding out how many minifig heads there actually are that have many different facial expression variations

(or heads that look enough like one another to be able to use them for the same figure(s)) - one figure I can think of is Emmet from The LEGO Movie, but which others are there?

Whether they're yellow or flesh, if you have any idea which heads could be used for many different facial expressions, let me know.

[Tariq j]

Louis Tully from the Firehouse has two heads with 3 different expressions.

[xboxtravis7992]

Tony Stark has three head pices, each are double sided. One might be hard to get though since it comes with an exclusive Polybag

[Blondie-Wan]

It's not a traditional minifigure head, but FWIW, SpongeBob Squarepants's head has a slew of variations - I think it's different in every set in which he appears, or close to it, and he appears in pretty much every set in a theme that ran for six or seven years.

Several Star Wars characters have had a bunch of variations over the years, though many of them are more about differences in art style than actual different expressions.

Edited March 28, 2016 by Blondie-Wan

[BattleBrik]

You can see any minifig head ever made here: http://www.minifigure.org/