I.Normal: Your average dumb zombie
A.Bloated: Fat zombie that takes breaks at corners. Squashes anything in it's way.
B.Speedster: Fast and short
1.Lurker: Hides in the shadows until player comes and strikes lightning fast.
C.Eating: Eats Stuff
1.Healer: Heals after eating
2.Shooter: Spits after eating
II.Armed: Have arms that make them deal more damage
A.Metal skull: Have a metal mask that protects them, at the cost of speed
I'm making a list of bosses. I'm planning to have a Hippo and a dino in there for you jacobperson. I'm already thinking of ways to make them a valid boss.
To anyone who wants interrupts me while I'm reading a book: