Source SDK 2013 community repos

The Source modding community has stepped up to maintain various repositories that include Valve's SDK code with various additions and bug fixes. Below is a list of some of these community created code repositories. If you've made your own GitHub repository and would like to release it to the general Source modding community, please feel free to add it to this list:

Repo	Description
Nbc66/source-sdk-2013-ce	Nbc66 & Ian B.'s repo contains the SDK 2013 source with bug fixes and optional enhancements/experimental additions. It also includes support for the v143 toolset which grants the ability to compile with VS2022, eliminating the need to use VS2013.
Creators-of-Strilling/AdrikikiSource	Adrikikicp's repo adds LUA support into the engine. Still being tested. Fork of Source: Community Edition
ozxybox/source-mp-vs2022	Ozxybox's rep contains the SDK 2013 source, tweaked to work with VS2022.
Mapbase	Improves the engine and entities to be more capable and stable for mapping and other kinds of modding without changing too much of the game itself. It's designed to be used as a platform for mappers to build their maps on and for larger mods to draw code from. Mapbase is generally used as a massive package of utility features and general-purpose fixes.
Map Labs	Map Labs is an ongoing anthology of Half-Life 2/Source Engine levels, all designed for the various Map Labs mapping challenges.
jimbomcb/source-sdk-2013 [dead link]	John McBroom's repo contains the SDK 2013 source with bug fixes.
saul/source-sdk-2013	Saul Rennison's repo contains the SDK 2013 source with bug fixes and a few features.
fuzzzzzz/source-sdk-2013 [dead link]	Nicolas Kirsch's repo contains the SDK 2013 source with bug fixes and a few features.
sandern/py-source-sdk-2013	Sander van Noort's repo contains the SDK 2013 source with auto generated bindings for Python 3
IVEngine 2	Huge changes to the gameplay and engine, including new GameUI.
tonysergi/source-sdk-2013	Tony "Omega" Sergi's fork, with some official changes that got lost in the transition to GitHub.
HL2MP Bug Fixes	Server sided fixes and optimization for HL2DM.
Source PlusPlus	SDK 2013 MP base with graphical enhancements such as render-to-texture shadows, cascade shadow mapping, uberlight, volumetrics.
Aurora Source	Aurorians's custom version of the Source SDK 2013
Vance mod source code	Fork of source code to the Vance mod, containing gameplay changes and graphical enhancements.
LUX	Rewrites default SDK and Mapbase shaders to fix bugs, decrease compile times, add features, etc.
Half-Life 2: Sandbox	A free and open-source sandbox Source engine modification.
source-sdk-vs2022	Source 2013 for VS2022 (original description)
source-sdk-2013-fmod	The 2013 edition of the Source SDK + FMOD integration
template-source-sdk-2013-lua	Fork of the 2013 edition of the Source SDK. It provides a minimal starting point for a multiplayer mod with Lua 5.4 embedded.
Director's Cut	A community-driven filmmaking tool built on Source.
source-code-tutorials	The 2013 edition of the Source SDK, including modifications from TheMaster974's Valve Source Code Tutorial & Source Shorts Series
source-sdk-2013-headers	Headers from 2013 edition of the Source SDK (original description)