Walker-the average zombie slow but roam in numbers.
Crawler-zombies who lost their legs and crawl instead of walking
Runner-evolved zombies that adapted to be able to chase humans
Brute zombie-these were former muscle builders or zombies that mutated to gain extra bulk have enough muscle memory to remember how to jump and even punch.
Caller-these zombies yell attracting others to their position creating hordes.
Demolisher-usually brute zombies or zombies that mutated to be the size of three humans stacked on top of each other use their big bulky arms to knock down walls but are extremely slow can only be taken down with explosives.
Pregnant-humans that got turned while pregnant can spit acid and birth baby zombies.
Exploder-zombies that explode upon death spreading an spore version of the virus that brings back dead creatures that haven't been shot in the head.
Hybrids-humans that we're immune to the virus that were bitten too much becoming half zombie half human they have control over zombies can turn other humans into hybrids and can control zombies.