More posibilities how to kill mobs/players
SFENCE

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

Visual Harm 1Ndicators
Mantar

HP bars for mobs/players

Traders
Sokomine

Configurable mobs/NPC which can trade for you.

Nether Mobs
Dirkfried

Add monsters and dragons to your nether world.

Mesebox
johalun

Mobile storage box powered by Mese

Not So Simple Mobs
TenPlus1

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

Moblib
LMD

Low-level high-performance entity library

Mobkit Sapien
LuantistDork

Adds villager like mobs using Mobkit.

Balrog Sword MT 5.4
DragonWrangler

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

Throwable Bombs
DragonWrangler

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

Lategame Amulets
Comet

A cohesive progression system that builds on Mobs Monster

Mob Crab (Beta)
Can202

Adds Crabs.

Mobs Skeletons
TenPlus1

Adds three skeletons to the world.

Mob Horse
TenPlus1

Adds rideable horse

Wilhelmines Living Caves Mobs
mt-mods

adds mobs to the caves of your world

Wilhelmines Marinara Mobs
Liil

adds mobs to the marinara oceans

Mob BiomeDb Mapper
Neuromancer

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

Alive AI
AiTechEye

Advanced survivor ai mobs (npc, monsters and more)

Mobs NPC
TenPlus1

Adds simple NPC and Trader.

3D Armor Mobile
LandarVargan

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

Vegan Misc.
AirplaneMan

Adds vegan alternatives for there are no mob drops avialable

Mob Mese Monster Classic
TenPlus1

Adds classic Mese Monster.

Common Mob Interface
Byakuren

A standard modding interface for interacting with mobs

Mob Biome Mapper
Neuromancer

Allows mobs to spawn in biomes that don't support them.

Banshee
ElCeejo

Adds Banshees, a ghostly mob that haunts pine forests

The Mob API
TX_Miner

Provides a simple API for mobs

Spawners
SaKeL

Adds spawners for mobs, dungeons, temples and ores.

Mobkit
mt-mods

Entity API

Mobs Monster
TenPlus1

Adds many types of monster.

Mobs Ethereal Bosses
PixelZone

Adds 3 bosses to some biomes..

Mobs Ghost Redo
TenPlus1

Adds ghosts.

Cube Mobs
Xanthus

Adds various cube mobs with different abilities using mobkit.

Living Slimes
EmptyStar

Adds living slime mobs

Mob Core
mt-mods

A Mob API meant to expand upon mobkit and bring easy to use features for creating new Mobs.

Disable Mob Damage for Advanced Trains
Silver Sandstone

Prevents trains from damaging mobs.

Zoonami 3D Mobs
isaiah658

Adds 3D monster mobs to Zoonami.

Slimes Redo
TenPlus1

Add green and lava slimes to your world.

Extreme Randomizer
NO11

Randomises crafting, mob and block drops.

Climbing Pick
lag01

Tool to climb, double jump, and do good damage to mobs.

Too Many Aliases
ThePython10110

Adds aliases to every item/node in MineClone to make them match MineCraft so you can stop forgetting that mcl_mobitems:ender_pearl should be mcl_throwing:ender_pearl.