If you have low fps download optifine:https://optifine.net/downloads I would've put it in the modpack but Curse didn't let me.
Also if you want to change the texture of the zombies download this texture pack:https://www.curseforge.com/minecraft/texture-packs/tissous-zombie-pack-optifine-1-7x-1-16
This modpack contains mods that turn the vanilla Minecraft experience into a Zombie Apocalypses where you have to fight through hundreds of infected zombies just to survive, thinking of hunkering down in your home? Well think again because the zombies can break blocks so really your not safe anywhere unless you get some defenses and turrets up. Feeling like there's nothing todo? well maybe you should start thinking about trying to rebuild society, with the "TekTopia" mod you can start making a village and really start to rebuild the world into a "normal" world like it used to be before it all happened.