Source

A modern customization framework for Team Fortress 2

Tool to mod Portal 2's Puzzlemaker

The Blender Source Tools add Source engine support to Blender, the free 3D modelling suite.

A more convenient alternative to Blender Source Tools.

Python library for analysing .bsp files

Modules for working with Valve's Source Engine file formats.

Source Engine level converter for Call of Duty.

Titanfall wiki about advanced topic such as modding, data-mining, reverse engineering, commands, etc.

A Python-powered gui for converting pbr materials into Source Engine-compatible materials.

A tool to optimise source engine content filesize

Import Source game content into Source 2

Essential tools for Counter Strike 2 Workshop Tools : SoundEvent Editor, SmartProp Editor, Hotkey Editor, Loading Editor

Scripting CS:GO over telnet.

scalu is an event-based programming language and compiler targeting config files in Valve's Source Engine

A python VMF parser

python alternative to Valve's "Hammer World Editor"

Blender plugin that allows for easier modding and animation of the Gold Source/Source/Titanfall armatures.

An open source, cross-platform audio player for Source and GoldSrc engine based games, written in Python

Tool for making Half-Life and other Valve games playable on modern ARM Macs

Half Life 2 ARM Patcher