Walker:Slow but deadly in numbers,know from experience.
Mutants:Scary,Fast,and hunt in packs in remote areas,so your fucked if you see one unless you have quick reflexes.Graboids:Zombies snakes that resemble the subterranean beasts.
SwarmZ:Fast swarm zombies based off the zombies from World War Z.
Blood Moon:This is from Unturned 3.0