Mod Loaders & Script Extenders (Game Decompilations & Reimplementations): open-source projects that exist because someone reverse engineered a closed product, sorted by GitHub stars.
Visual novel translator that hooks game text from running Windows games
Plugin/modding framework for Unity Mono, IL2CPP and XNA games
Modding API and loader for Minecraft: Java Edition
Library for patching and decorating .NET/Mono methods at runtime, widely used for game mods
Mod loader and API for Terraria
Mod loader, scripting platform and VR support for Capcom RE Engine games
Replaces DLSS Frame Generation with FSR 3 frame generation in games
Cyberpunk 2077 scripting framework and fixes
Universal VR mod injector for Unreal Engine 4.8-5.x games
Universal mod loader for Unity games (Il2Cpp and Mono)
Multiplayer modification frameworks for GTA V (FiveM) and RDR2 (RedM)
DirectDraw reimplementation fixing old games such as Command & Conquer on modern systems
Fixes and enhancements for Grand Theft Auto IV: Complete Edition
Plugins adding or fixing widescreen support and bugs in many PC games
In-game UI for exploring and modifying IL2CPP and Mono Unity games
Injectable Lua scripting, SDK generator and live property editor for UE4/UE5 games
Terraria server modification and plugin API
Modding API and loader for Stardew Valley
Proxy DLL that loads custom .asi plugins into any game process
Game modding and enhancement framework for Windows games
Modding API and loader for Minecraft: Java Edition
Multiplayer engine for GTA: San Andreas
Brood War API for writing StarCraft: Brood War AI bots
Mod loader for Minecraft Bedrock Edition dedicated server
Plugin framework and API for Final Fantasy XIV
Modern Mod Coder Pack for decompiling and modding Minecraft Java
Baldur's Gate 3 Script Extender
C# server plugin framework for Counter-Strike 2 built on reverse engineered Source 2 internals
.NET scripting runtime for Grand Theft Auto V on top of Script Hook V
DirectX 11 wrapper for shader modding and stereo 3D fixes in games
Open Minecraft deobfuscation mappings for modding
Fixes for GTA III, Vice City and San Andreas made by patching the game binaries
Skyrim Together multiplayer mod built on reverse engineered engine internals
Runtime injection library for modding FromSoftware Souls games
In-game inspector and debugging tools for Unity games
Universal .NET-powered modding framework for native x86/x64 games
Mod loader for Balatro
Super Mario 64 (N64) as a library for use in other game engines, from the decompilation
Steam Play compatibility tool that runs games with native Linux engine reimplementations
Rust mashup of the IW4L Modern Warfare 2 rewrite with Skate 3 and Minecraft modes (PC)
Mod loader for Minecraft: Java Edition
New Vegas Script Extender
Runtime mod loader for Final Fantasy XIV
Touhou Community Reliant Automatic Patcher: patching and translation framework for Touhou games
JavaScript plugin loader for the League of Legends client
Generic mod loader for Godot games
SDK for ASI/CLEO plugins for GTA III, Vice City and San Andreas
Mod Engine 3, a framework for modding and instrumenting FromSoftware games
Multiplayer mod for GTA San Andreas, backwards compatible with SA-MP
Game patches such as frame-rate and resolution fixes for the Xenia Xbox 360 emulator
Runtime Lua injector for LOVE2D games such as Balatro
Mod manager and loader for Unity games
Generates managed proxy assemblies for IL2CPP Unity games so they can be modded
Next-generation modding platform and driver for Final Fantasy VII and VIII PC
Celeste mod loader and mod API
External mod loader for Slay the Spire
Script extender for REDengine 4 (Cyberpunk 2077)
Mod loader and manager for Sonic Hedgehog Engine games
Engine extension for C&C Red Alert 2: Yuri's Revenge
Minecraft Bedrock Dedicated Server modding with Node.js
Mod loader and integration for Deep Rock Galactic
sfall - Engine modifications for Fallout 2
Fixes and improvements for the PC ports of Kingdom Hearts
Mod loader for Grand Theft Auto III, Vice City and San Andreas
Mod Coder Pack for decompiling and recompiling old Minecraft versions
Mod loader for Hatsune Miku: Project DIVA Mega Mix+
Modding framework for Super Smash Bros. Ultimate file replacement
Rust game extension for the Oxide modding framework
Mod loader for Anno 1800
Script extender for The Binding of Isaac: Repentance
Starfield Script Extender
Skyrim Special Edition Script Extender
Unofficial mod loader for Satisfactory
Modding API for Hollow Knight built by patching game assemblies
Reverse engineered native class layouts of the Final Fantasy XIV client
Binary patch that fixes technical issues in American McGee's Alice (PC)
Cross-platform mod loader and merger for The Legend of Zelda: Breath of the Wild
Oblivion Script Extender
Runtime hooking and code patching environment for Nintendo Switch games
Modding toolkit for Arknights: Endfield on Windows and Android
Adds VR support to flatscreen Unreal Engine games
Modding SDK and mod loader for Hitman World of Assassination
Unofficial SDK for Rocket League modding with BakkesMod
MetaHook plugin loader ported to the Sven Co-op GoldSrc engine
Modding API for Among Us
Universal mod loader for Unreal Engine 4 games
Reverse-engineered C++ library of Skyrim SE game types for plugin development
Localization hook for the Umamusume Pretty Derby DMM client
Multiplayer mod for Touhou Mystia's Izakaya
Single-screen and frame interpolation patch for Majora's Mask 3D (3DS)
Unity mod injector built for Beat Saber
Mod manager for Diablo II: Resurrected
Mod manager and code loader for Sonic the Hedgehog PC games
SKSE plugin that fixes Skyrim Special Edition engine bugs
Elden Ring mod that adds Super Mario 64's Mario via libsm64 (PC)
Mod loader and runtime script patching for Godot games
Script extension library for GTA San Andreas
English translation patch for Princess Connect! Re:Dive (JP Windows client, IL2CPP)
Mod manager for Mass Effect trilogy and Legendary Edition
Mod project development environment for Unity games
Unpacks FromSoftware game archives so mods can load loose files
Experiment that runs Spider-Man Remastered and Arkham Knight together with shared collision
Mod loader for My Summer Car and My Winter Car
Mod loader for Elden Ring
Mod loader for Hacknet: Labyrinths
Plugin loader and engine fixes for Kenshi
Minecraft mod that adds Super Mario 64's Mario via libsm64 (PC)
Modding API for Risk of Rain 2
Mod loader, injector and decompiler for Balatro
Quality-of-life mod framework for Mabinogi
Engine patch with fixes and AI improvements for Sid Meier's Alpha Centauri: Alien Crossfire (PC)
Fallout 4 Script Extender
Launcher that adds engine updates to SAGE engine games (C&C Generals, Battle for Middle-earth)
ASM codes adding rollback netplay and replay recording to Super Smash Bros. Melee
Modding library for Valheim
Patch that makes Worms 2 run on modern computers with extra features
Mod loader for Subnautica and Below Zero
Fixes and extensions for Bethesda's Creation Kit built from reverse engineering
Mod loader for GTA: San Andreas on iOS
Mod loader for WorldBox
Gameplay overhaul mod for Dark Souls built via reverse engineering
Cyberpunk 2077 modding tool for loading custom resources without archive conflicts
Cyberpunk 2077 modding tool for TweakDB edits
NieR: Automata multiplayer mod
Unofficial Final Fantasy VIII Remastered core mod
Reverse engineering and fixes for Skyrim Special Edition
Morrowind Script Extender with Lua scripting
Garry's Mod addon that adds Super Mario 64's Mario via libsm64 (PC)
Patched Terraria server assembly exposing hooks for modding
Lightweight mod loader and API for Minecraft 1.13
Tool to inject translated strings into games through low-level code hooks
Mod loader for Resonite
Add-on and fixes for Assassin's Creed Unity
GTA San Andreas mod that adds Super Mario 64's Mario via libsm64 (PC)
Reverse engineering, menu and patches for Tomb Raider Legend/Anniversary/Underworld
Mod loader for Android games and applications
Mod loader and library for Outer Wilds
Mod loader for Sons of the Forest
Localization and enhancement mod for the Uma Musume Windows client
Mod loader for Rust game servers
Mod loader for the Minecraft Bedrock dedicated server
Mario Kart Wii mod with features built on reverse-engineered game code
Medieval II: Total War Engine Overhaul Project
Open-source plugin providing fixes and features for Rock Band 3
Collaborative reverse engineered library for Starfield modding
Installer for Millennium, a Steam client theming and plugin loader
Mod loader for The Battle of Polytopia
Reverse engineered library for Fallout 4 modding
Patch for Worms Armageddon that modernizes the game
Cross-platform, cross-version mod loader for Godot games
Extension for the Red Alert 2 Final Alert 2 map editor
Silent Hill 2 mod loader and camera mod
C++ SDK for creating code mods for Spore
Rust tools and integrator for modding Unreal Engine games
Mod loader for OMORI
Mod loader for Muse Dash
Mod loader for The Crew and The Crew 2
Rust bindings to Elden Ring, Dark Souls 3, Nightreign and Sekiro internals
Modding framework for Prey (2017)
Elden Ring API library focused on binary compatibility
Mod loader for Oxygen Not Included
Mod loader for Dynasty Warriors 8: Xtreme Legends and Warriors Orochi 4
Game-agnostic N64 mod loader built on Mupen64Plus
Mod loader for Sonic Adventure DX PC
Multiplayer co-op mod for Voices of the Void (UE4SS)
Mod loader for Ballance
C# plugin loader for Monster Hunter World
Lua mod loader for Into the Breach
Oblivion Remastered Script Extender
Baldur's Gate 3 Script Extender replication for macOS
Mod loader for CrossCode
Mod loader for Sonic Adventure 2 PC
Morrowind Graphics Extender XE: renderer and engine extensions for The Elder Scrolls III: Morrowind
Android port of the umamusume-localify localization mod
Mod loader for Slime Rancher
Mod loader for Earth Defense Force 4.1, 5 and 6
Mod loader for Besiege
ASI plugin that adds custom resolutions and frame rates to Final Fantasy Type-0 HD
Extension plugin for the New Vegas Script Extender
Mod loader for Neos VR
Mod loader for Buckshot Roulette
Halo: CE (MCC) mod that adds Super Mario 64's Mario via libsm64 (PC)
Harmony patching library packaged for Mount & Blade II: Bannerlord mods
Custom music player replacement for Need for Speed games
Mod loader for Football Manager 26
Mod loader for Sonic Mania
Reversed types of BlackBox-era Need for Speed games for plugin and script mods
Mod loader for Mega Man Battle Network Legacy Collection
Mod loader and injector for BattleTech
Mod loader and API for Enter the Gungeon
Randomizer and mod loader for various games
Clean-room Wii disc mod loader with SD packages, runtime patching and save redirection
Reverse-engineered modding headers for Minecraft: Bedrock Edition
Mod loader for Silent Hill 4: The Room
Mod loader for Warhammer 40,000: Darktide
Mod loader for OMORI
Mod loader for the Steam version of Persona 4 Golden
Astroneer mod loader written in Rust
Deprecated universal C# DLL injection mod loader (predecessor of Reloaded II)
Mod that restores and adds functionality to the Halo 2 Editing Kit
Free camera, first-person mode and other additions for Manhunt
Adds mouse control to Touhou Project games
Mod loader for Minecraft Legacy Console Edition
Modding framework for Stationeers
CnCNet spawner DLL for Command & Conquer: Yuri's Revenge
Mod loader for Road to Vostok
Limit adjuster that patches GTA III, Vice City and San Andreas executables
GTA San Andreas plugin SDK extended from a fully reverse-engineered codebase
Multiplayer mode for Alien Shooter (2003)
Mod loader for the PC versions of Persona 3, 4 and 5 Royal
Unofficial mod support for PULSAR: Lost Colony
Function hooker for cooked Unreal Engine blueprints
Function hooking and mod loader for Beat Saber on Oculus Quest (IL2CPP)
Experimental mod loader for Enshrouded
Mod loader for SCP: Secret Laboratory
Mod loader and modding API for GDevelop games
Character script mod loader and QoL mod for Guilty Gear Xrd Rev 2
C# modding API for No Man's Sky built on Reloaded II
Native mod loader for Baldur's Gate 3
Mod loader for Disney Infinity 3.0 (PC, Octane engine)
Mod loader for Cruelty Squad
Patches for Demon's Souls that enable debug menus and other functions
Widescreen and compatibility patch for Emperor: Battle for Dune on modern Windows (PC)
Mod loader for Jalopy
Mod format and loader for Supergiant Games titles (Bastion, Transistor, Pyre, Hades)
Balatro mod loader and injector for PC, iOS and Android
Modular Unreal Engine mod loader written in C#
Mod loader for the 2004 PC version of Sonic R
Mod loader for Grim Fandango Remastered
Mod loader for FEZ
Renovated mod loader for Ballance
C code injection framework for PS3 games
DLL mod loader for freeware Cave Story
Modding library for Streets of Rogue
Mod loader and manager for Spore
Script extender for Frontier's Cobra engine games
Mod loader for TowerFall
Embedded mod loader for Wii games
Mod loader for Middle-earth: Shadow of War
Real-time online multiplayer for Worms Armageddon
Mod loader for Hades II
Software development kit for modding the Steam version of Mafia II
REST server for X4: Foundations game state
Script extender DLL patch for Civilization VI
Mod loader for Distant Worlds 2
Mod manager and loader for A Hat in Time
Mod loader for Opus Magnum
Resident Evil 1 gameplay systems ported into GZDoom using the RE1 PC decompilation
Mod loader for Risk of Rain 2
Loads blueprint pak mods for Star Wars Jedi: Fallen Order
Mod management for Spelunky 2 via DLL injection
Plugin base for PSP game modding and code injection
Custom launcher for Ratatouille (PC)
OBSE plugin that overhauls the Oblivion Construction Set
Loads CPK mods and DLL plugins into NieR:Automata
Script extender for REDengine 3 (The Witcher 3)
Lua mod loader for Risk of Rain Returns
Mod loader for Sonic 4 Episode 1 and 2
Controls, gameplay and presentation enhancements for the Perfect Dark Zero recompilation
Bannerlord Software Extender: loader for Mount & Blade II: Bannerlord
Mod loader for OneShot: World Machine Edition
Launcher and mod loader for HoloCure
Java mod loader for Project Zomboid based on Mixins
Mod loader and manager for Phoenix Point
Script-extending resource for Skyrim mod authors
Co-op play of the Deus Ex campaign over Steam: HX mod fixes and a Steam relay
Mod loader for GameMaker Studio games built on UndertaleModLib
HoloCure mod loader written in C#
Mod loader for Luck be a Landlord
DLL mod loader for Age of Empires II: The Conquerors
Injectable DLL for writing custom Deep Rock Galactic modifications
Patching toolchain for injecting code into Nintendo DS games
Script extender for Kenshi
Lua scripting extension for Kenshi
Original script extender for Fallout: New Vegas
Mod loader for SNKRX
Mod loader and framework for My Singing Monsters (PC)
Patches for the reverse-engineered Space Rangers HD source for Linux and Windows builds
Harmony-based mod loader for DREDGE
Runtime renderer optimization for F1 25 via reverse-engineered settings hooks
ASI mod loader and modding API for Croc 2
Runtime and modding toolkit for OMORI that plays your own copy in the browser
Mod loader for Rogue Legacy 2
Mod loader for Homeworld: Deserts of Kharak
Plugin loader for Monster Hunter: World (PC)
Converts Banjo-Kazooie ROM hacks into Banjo: Recompiled mods
Core utilities library for building game script extenders
Mod loader for Android games (Smash Hit, Granny Smith)
PS2 modding toolchain experiment
Crash Team Racing kart physics from its decompilation, ported into the benilla WoW client
Gameplay modifiers for Touhou 8, built on its reconstructed source
Whitebox reverse-engineered codebase of the Silkroad Online client