There are 2 repositories under hl2 topic.
Fragsurf is an actively developed standalone game based on HL2 surf and bhop movement mechanics.
Prometheus Exporter for SRCDS game servers, working with CSGO, CSS, GMod, HL2, L4D2 and TF2 !
Used to parse source demos.
Porting Half-Life 2 base to the Alien Swarm Engine
BrainBread 2 Source Code
☢️ An up-to-date Source Server Query protocol library written in C99
Team Fortress 2 server plugin that allows players to sprint like in Half-Life 2
A collection of maps for Source Engine based mods.
An addon for Garry's Mod that mimicks the Heads Up Display feature from Valve's 2004 game Half-Life 2 adding a deep customization layer to it.
Fixes a bug that reduces air-acceleration while crouched in CS:S
This repository acts as a diff checker for gamemovement.cpp from the Source SDK 2004 to the HL2/CSGO 2018 leak, additionally tracks more comprehensive updates made in the CSGO engine branch.
Half-Life: Blue Shift Co-op
Half-Life 2 related tools for Garry's Mod Sandbox gamemode
半条命 2 模组 - 用郊狼⚡模拟一下自己和敌人的受伤痛觉~ | Half Life 2 DG-Lab Mod
Half-Life 2 weapons for Sven Co-op
https://forums.alliedmods.net/showthread.php?t=267805
A simple Blazor powered game server browser
HGSM-HattrickGameServerManager
Source SDK 2013 Custom Edition
Infestus's Web App (ASP.NET & Vue.Js)
HL1/ HL2 Rcon Studio
The complete source code of Contingency, a Half-Life 2 modification built using the Source engine.
Modified source engine (2017) developed by valve and leaked in 2020. Not for commercial purporses
A source game map tester wrote for SourceMod that runs through every map to find out if it crashes server
Compiled and Fixed VMFs from the leaked WC map pack for Leak and Retail HL2
Valve's VRM format documented.
INSURGENCY: Modern Infantry Combat for SDK 2013
python script to help with tricksurf mapping. automatically generates triggers to cover surfaces in counter-strike: source maps. work in progress.. supports hammer++ vmf only
Generates and compares entity definitions from FGD data for backporting maps… made for porting csgo maps to css