More posibilities how to kill mobs/players
SFENCE

Add more posibilities how to kill mobs and/or players, like traps, throwable TNT, etc.

Traders
Sokomine

Configurable mobs/NPC which can trade for you.

Visual Harm 1Ndicators
Mantar

HP bars for mobs/players

Not So Simple Mobs
TenPlus1

Adds a host of creatures into your world with new weapons too.

Mobs Redo API
TenPlus1

Simple and feature rich API to quickly add mobs into your world.

Mob Mese Monster Classic
TenPlus1

Adds classic Mese Monster.

Alive AI
AiTechEye

Advanced survivor ai mobs (npc, monsters and more)

New mobs for Mineclonia
michi16bit

Add minecraft mobs and items

Mobs Animal
TenPlus1

Adds farm animals.

Living Slimes
EmptyStar

Adds living slime mobs

Balrog Sword MT 5.4
DragonWrangler

allows those using the old mobs balrog mod to have balrog swords

Mobkit
mt-mods

Entity API

Creatura
ElCeejo

A performant, semi-modular, Animal focused mob API

Throwable Bombs
DragonWrangler

adds a cave expansion tool, a throwable tnt stick, a throwable smoke bomb, and a mob throws tnt

Mobs Ethereal Bosses
PixelZone

Adds Bosses in biomes from the "Ethereal NG" and "Mineclonia" mods

Mobs Effects
SFENCE

Provides predefined attribute effects without apply logic for mobs based on Mobs Redo API, modifying movement, combat, and behavior attributes

MFSM Multiple Finite State Machine
Sumi

Allows for multple states to be active, while maintaining typical state machine behavior. Good for gamestate and mobs.

Extreme Randomizer
NO11

Randomises crafting, mob and block drops.

More Danger
Twinsonian

Scaling difficulty multiple games/mob apis. Based on the difficulty mobs will have faster movement speed, more damage and more health.

Mob BiomeDb Mapper
Neuromancer

Allows mobs to spawn in biomes that don't support them (Using info from BiomeDb)

3D Armor Mobile
LandarVargan

Adds a command to bring up a formspec that allows mobile users to put on armor

Common Mob Interface
Byakuren

A standard modding interface for interacting with mobs

Lategame Amulets
Comet

A cohesive progression system that builds on Mobs Monster

Mobs NPC
TenPlus1

Adds simple NPC and Trader.

Wilhelmines Living Caves Mobs
Liil

adds mobs to the caves of your world

balrog (flux's fork)
fluxionary

adds balrogs.

Disable Mob Damage for Advanced Trains
Silver Sandstone

Prevents trains from damaging mobs.

Mobs Skeletons
TenPlus1

Adds three skeletons to the world.

Zoonami 3D Mobs
isaiah658

Adds 3D monster mobs to Zoonami.

Mob Horse
TenPlus1

Adds rideable horse

Wilhelmines Marinara Mobs
Liil

adds mobs to the marinara oceans

Raids
DragonWrangler

Allows server owners or server admin to start mob raids to attack settlements or players

Spawners
SaKeL

Adds spawners for mobs, dungeons, temples and ores.

Invisiblocks
TenPlus1

Add invisible barrier, light and mob wall into game with new tool

Mobs Monster
TenPlus1

Adds many types of monster.

Banshee
ElCeejo

Adds Banshees, a ghostly mob that haunts pine forests

Mobkit Sapien
nurd3

Adds villager like mobs using Mobkit.

Mobs Ghost Redo
TenPlus1

Adds ghosts.

mime (flux's fork)
fluxionary

adds a monster mimicking its surrounding nodes.

Water Mobs
TenPlus1

Water Mobs for Mobs Redo