Minecraft Java 1.21 Mods
Browse 107 free mods for Minecraft Java 1.21 — popular picks include MythicKorra - Advanced ProjectKorra & MythicMobs Integration Addon, Godmode- wither rework, Project: TitanSlayer.
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MythicKorra - Advanced ProjectKorra & MythicMobs Integration Addon
Expand your MythicMobs bosses with element-based mechanics, statuses, conditions and more!
Godmode- wither rework
This mod entirely reworks the wither boss in minecraft, with custom loot, moveset, etc
Project: TitanSlayer
Slaughter Mobs and Bosses in a Doom Style

CobbleCatalyst
Adds Cobblemon trainer battle phases to Cataclysm boss fights, turning boss fights into hybrid combat and Pokemon battle challenges.
Inferno World
Dimension, epic boss battle, and tools inspired by a magical hell
WarFmod
A mod that adds new mobs and bosses to your world, as well as new features and items.
Sculk Wrath
Sculk Wrath is a complete Warden boss overhaul datapack that transforms the Warden into a 4-phase boss fight with custom attacks, boss bar, music, configurable drops, and dramatic animations.
Custom Boss Zoryth AI
Zoryth AI Boss is a premium, high-performance custom boss framework for Paper (1.21.x).
Artifacts and Bosses
This mod adds new gems that can be collected from 4 new bosses
Zombieium
Zombieium adds configurable night-time zombie waves and an optional boss encounter with a red warning beam, fiery arrival effects, and unique drops.
BossBarUltra
Modern floating health bars for mobs using Minecraft’s TextDisplay system. Lightweight, customizable, and perfect for RPG and PvE servers.
BossHeart
A mode that makes playing more comfortable
Folded Iron
A boss/item/weapon/after game content mod
MOAR Tools
MOAR Tools is a progression and combat expansion mod that adds three new gear tiers, two dungeon systems, a full boss encounter, and a suite of custom mobs all designed around a dark, End-themed aesthetic.
Steve's Custom Bosses Data pack
This data pack adds custom recipes, advancements, challenges, and bosses to the game, all with vanilla mechanics!
Custom Boss Template
Easy custom boss template for Minecraft 1.21+. Fully configurable health, name, appearance, phases, attacks, messages and rewards. Perfect for adventure maps and servers.
Monsterwalll's Bosses And Stuff
A mod I made that adds Bosses, Structures and more! Note that this is my first mod so please comment what you think should be fixed in future mods.
Endorium Mod
Endorium is an end-game expansion mod for Minecraft that introduces a new mini boss, new wood type and new tier of equipment beyond Netherite.
chicken boss
Adds a powerful God Chicken boss that attacks players by spawning creepers and iron golems.
Telum Solaris - At the Forest's Edge
Telum Solaris aims to add new weapons, armor and boss to minecraft for every stage of minecraft's progression. It is currently my first and only project!
BulsciCraft
Enjoy this brand new mod that adds New Dimensions, Mobs, Items, Blocks, Unusual things and even a bossfight...
NxControl
NxControl is an advanced staff plugin that lets OP players control players or mobs using simple keybinds, with GUI, bossbars, and freeze system built-in. It’s lightweight, powerful, and perfect for moderation, trolling, or cinematic gameplay.
Boss Radar
Craft a special compass that senses powerful mobs lurking nearby. Hold it to see a color-coded ring around your crosshair with the boss's name and distance, turning red as danger closes in — perfect for staying alert to the Ender Dragon, Wither, Warden

randomitems-mod
Adds /randomitems, /randommobs, /randomweapon, /randomarmor, /randomtool and /randomquest commands that periodically give random items, spawn random mobs, swap your gear, or assign 5-minute random quests with a boss bar and personal sidebar.
Chariz's Mayhem
A Minecraft Mod That Aims To Add Fun Things Into Minecraft, Such As New Mobs, Bosses, Weapons, Tools, Armor etc. Created By The Maniac Himself, DarkChariz
Endless Instability
This mod changes many stages of Minecraft, adding new blocks, tools, and bosses. It's not yet finished and is in early development. It's 70% translated into English and 100% into Russian.
MashStrikeDrops
The plugin is aimed at event servers, crates-style mob encounters, grind zones, boss-lite content, and custom reward systems without needing MythicMobs or a larger RPG stack.
Dragonfight Updated
This datapack is an improvement of the dragon fight. With a new mini-boss and even more.
Attrition
A world that answers your progress. 600+ mechanics: bleeding, thirst, curses, diseases, rebuilt bosses and a world that learns from every mob you kill.
Endmode 2 | Terraria Style Datapack
Terraria inspired overhaul to progression. New bosses, items, etc.

Calamity Bosses
20 NEW bosses that will shift the power changes in your world, adding custom item rewards and custom blessings to ease your fare through this treacherous world.
Neo The Titans Mod (1.21.4) – Discovering The Titan Gods of Minecraft
Neo The Titans Mod is a Minecraft mod that introduces powerful, genetically enhanced Titan bosses. It recreates the classic Titans concept while improving balance, performance, and compatibility with newer game mechanics. Features: Large Titan boss creatures with unique abilities and attacks. New equipment, tools, and ores related to Titan progression. Improved boss animations and smoother […]
BetterBoss
Strengthen weak bosses to make them easier to fight.
Wither Away
Provides configuration options to mute Wither-related sounds (global spawn, explosions, ambient) and toggle visual effects like the boss bar and screen darkening.
KingCraft [FORGE]
Travel to a different planet? Fight new bosses? Discover new game mechanics? Welcome here.
The Fallen World
This mod adds things like dimensions, blocks, items, mechanics, bosses, mobs, structures and much more!