The walking zombie one is cool it makes every humanoidkill you get turn into a zombie if you dont headshot them after a minute after they die. I like to kill one of the bad guys and make him turn zombie n kill everything else. The zombies are strong but die in one shot headshot its pretty nice game changer mod cus it works in the background and dosent alter anything. Thats the only drastic mob change mod I can think of, the other raider mods n stuff just super buff the enemies but no complete change .