Visit

 https://coros.us/mods/zombieawareness

for a much better showcase of the mod with images and videos

1.16.5 / 1.17.1 / 1.18.1:

- Blood scents: You spill blood if you get hurt, and if low health you bleed out once in a while
- Sound sources: causing these will alert other monsters of your position, they are:

-- Mining for blocks, Placing blocks, Explosions, Bows and Crossbows, Eating, Doors, Gates, Notes, Records, Buttons, Levers, Pressure Plates, Tripwires, Chests, Barrels, Pistons, Other zombies

- Light sources: Zombies can see exposed light sources from super far away, and will come to investigate if they have line of sight
- Random wandering hordes on surface (default off): Mobs will gather up together and wander the terrain in large groups randomly

- Default enhanced mobs (configurable): "minecraft:zombie", "minecraft:husk", "minecraft:creeper", "minecraft:skeleton", "minecraft:stray", "minecraft:witch", "minecraft:zombie_villager" 

- Radioactive glowing blood, definitely not a lighting bug for now.

1.12:

- Blood scents: You spill blood if you get hurt, and if low health you bleed out once in a while
- Sound sources: Mining for blocks will alert other zombies of your position
- Light sources: Zombies can see exposed light sources from super far away, and will come to investigate if they have line of sight
- Night surface spawning: More zombies spawn in groups at night, causes random invasions
- Random wandering hordes on surface (default off): Mobs will gather up together and wander the terrain in large groups randomly
- Randomly faster zombies: Zombies are given a small buff in speed to add more unpredictableness

Requires CoroUtil

You may use the mod in any modpack you like.