This collection of mods is mainly a hardcore world with a lot of opportunities to implement your projects and ideas.
I highly reccomend to play this modpack with your friends.

Here are a few features that are in this modpack:

New healing and damage system.

Added body parts that can stop functioning if severely damaged, so you should monitor your health. All this is provided by the "First Aid" mod.

Craftable guns.
Added craftable, realistic looking guns. Provided by the "MrCrayfish's Gun Mod" and "Stabx Modern Guns" mod.

New realistic zombie behavior.

Now zombies are really dangerous to fight. They can break blocks, make groups and kill you easily. Provided by the "Zombie Awareness" and "Improved Mobs" mod.

I highly reccomend to play with "Optifine"

All mods from the modpack links below:

Mouse Tweaks (by YaLTeR)
Create (by simibubi)
Fresh Animations (by Fresh__LX)
Zombie Awareness (by Corosus)
First Aid (by ichttt)
LambDynamicLights (by LambdAurora)
Xaero's Minimap (by xaero96)
Chunk Animator (by Lumien231)
MrCrayfish's Furniture Mod (by MrCrayfish)
CreativeCore (by CreativeMD)
Tissou's Zombie Pack (by Tissou)
GeckoLib (by Gecko)
Create Crafts & Additions (by MRHminer)
Immersive Engineering (by BluSunrize)
Sophisticated Backpacks (by P3pp3rF1y)
Tough As Nails (by TheAdubbz)
Sophisticated Core (by P3pp3rF1y)
MrCrayfish's Gun Mod (by MrCrayfish)
Stabx Modern Guns (by stabilizer_king)
AmbientSounds 5 (by CreativeMD)
Just Enough Items (JEI) (by mezz)
Naturalist (by Starfish_Studios)
Framework (by MrCrayfish)
CoroUtil (by Corosus)
TenshiLib (Forge) (by flemmli97)
Improved Mobs (Forge) (by flemmli97)

The Ultimate Zombie-Apocalypse Pack

AmbientSounds 6

Chunk Animator

CoroUtil

Create

Create Crafts & Additions

CreativeCore

First Aid

Framework

Fresh Animations

GeckoLib

Immersive Engineering

Improved Mobs (Forge, NeoForge)

Just Enough Items (JEI)

LambDynamicLights

Mouse Tweaks

MrCrayfish's Furniture Mod (Legacy)

MrCrayfish's Gun Mod

Naturalist

Sophisticated Backpacks

Sophisticated Core