Random Mob Effects

Random Mob Effects is a configurable mod created to make the game a little more difficult. Every hostile mob receives a random potion effect upon joining the world. There are a few potion effects disabled by default, which can be changed in the config via an in-game effect picker. The effect applied has a duration of the maximum integer value in java, which is 2147483647 ticks; around 30000 hours in-game. The particle effect can be disabled.

All available config options:

potionEffectLevel default 1, min 1, max 50
The default level of the effects the mod applies, by default 1.

hideEffectParticles default false
When enabled, hides the particles from the mobs with an effect.

disableCreepers default true
Creepers can create infinite lingering potion effects which is probably not what you want. When enabled, the mod doesn't give creepers a random effect.

effectBlacklist default "minecraft:instant_health,minecraft:instant_damage,minecraft:invisibility,minecraft:wither,minecraft:glowing,minecraft:levitation,minecraft:bad_omen,minecraft:hero_of_the_village"
A comma separated list of effect ids that mobs never get. Use * as a wildcard.

Hostile mobs with their random effects:

You may freely use this mod in any modpack, as long as the download remains hosted within the CurseForge or Modrinth ecosystem.

Serilum.com contains an overview and more information on all mods available.

Comments are disabled as I'm unable to keep track of them across so many separate mod pages.
For issues, ideas, suggestions or anything else there is the Github repo. Thanks!