Source code of this mods is available for modders and porters in public access.
Official gitlab repository - https://gitlab.com/Cobalt-57/half-life-absolute-zero/
Official github repository by Martin "Bullet" Webrant - https://github.com/martinwebrant/agmod
Mirrored on github - https://github.com/JoelTroch/am_src_30jan2011
Mirrored on github - https://github.com/JoelTroch/am_src_rebirth
Mirrored on github - https://github.com/nekonomicon/BattleGrounds
Download page on official site(WM snapshot) - http://www.bubblemod.org/dl_default.php
Mirrored on github - https://github.com/HLSources/BubbleMod
Official github repository - https://github.com/CKFDevPowered/CKF3Alpha
Version 1.9 is available on ModDB - https://www.moddb.com/mods/cold-ice/downloads/cold-ice-sdk
Version 1.9 mirrored on github - https://github.com/solidi/hl-mods/tree/master/ci
Mirrored on github - https://github.com/solidi/hl-mods/tree/master/cir
Uploaded to github by Oleg Cherkasky - https://github.com/gunrunners-paradise/Cthulhu-HLmod-SDK
Available in Valve's Half-Life repository - https://github.com/ValveSoftware/halflife/tree/master/dmc
Official github repository - https://github.com/adslbarxatov/xash3d-for-ESHQ
Available on GamerLab - http://gamer-lab.com/eng/code_mods_goldsrc/Half-Life_2D_(Flat-Life)
Mirrored on github - https://github.com/nekonomicon/gw1.45src
Versions 2.0 and 3.0, available in mod archives on ModDB - https://www.moddb.com/mods/go-mod/downloads
Version 3.0, mirrored on github - https://github.com/nekonomicon/Go-mod30
Available on GamerLab - http://gamer-lab.com/eng/code_mods_goldsrc/GT_mod_(Polnie_ishodniki)
Mirrored on github - https://github.com/solidi/hl-mods/tree/master/hla
Mirrored on github(PC Port) - https://github.com/hoaxer/Half-Life-Decay
Available on ModDB - https://www.moddb.com/mods/half-life-echoes
Available on ModDB - https://www.moddb.com/mods/half-life-expanded-arsenal
Branch gravgun in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/gravgun
Official github repository - https://github.com/jlecorre/hlinvasion
Mirrored on github - https://github.com/solidi/hl-mods/tree/master/pong
Available on cs-mapping.com.ua - https://old.cs-mapping.com.ua/forum/showthread.php?t=38030
Official gitlab repository - https://gitlab.com/Sockman/hltopdown
Official github repository - https://github.com/Fograin/hl-subsmod-ex
Official gitlab repository - https://gitlab.com/hlrally/src
Available on ModDB - https://www.moddb.com/mods/half-life-weapon-edition/downloads/half-life-weapon-edition-1508-alpha-open-src
Available on ModDB - https://www.moddb.com/mods/year-of-the-dragon
Available on ModDB - https://www.moddb.com/mods/half-nuked/downloads/half-nuked-src
Official github repository - https://github.com/suXinjke/HalfPayne
Official github repository - https://github.com/muddasheep/hqtrilogy
Official github repository - https://github.com/HeathGames/half_rats_parasomnia_src
Official github repository - https://github.com/desukuran/half-screwed
Version 1.3 on ModDB - https://www.moddb.com/mods/headcrab-frenzy/downloads/headcrab-frenzy-13-beta-source-code
Mirrored on github - https://github.com/nekonomicon/HeartOfEvil
Official SourceForge repository - https://sourceforge.net/projects/icm-hl/
Official github repository - https://github.com/vermagav/mechmod
Available on GamerLab - http://gamer-lab.com/eng/code_mods_goldsrc/Mortal_Combat_Forever_(Polnie_ishodniki)
Official github repository - https://github.com/unknownworlds/NS
Available in mod archive on ModDB - https://www.moddb.com/mods/overturn
Mirrored on github - https://github.com/nekonomicon/OZDM
Available on ModDB - https://www.moddb.com/mods/paranoia/downloads/paranoia-toolkit
Prealpha, mirrored on github - https://github.com/a1batross/Paranoia2_ancient
Version 1.51, mirrored on github - https://github.com/a1batross/Paranoia2_original
Unfinished mod
Was found on HLFX - http://hlfx.ru/forum/showthread.php?s=2c892dfc52f72be52a89c3f52a397cd0&threadid=1819&postid=44674#post44674
Available in Valve's Half-Life repository - https://github.com/ValveSoftware/halflife/tree/master/ricochet
Logic&Trick's mirror - https://files.logic-and-trick.com/#/Half-Life/Mods/Spirit%20of%20Half-Life
Version 1.5: mirrored on code.idtech.space - https://code.idtech.space/vera/halflife-thewastes-sdk
Unfinished mod by Valve Software
Available in Valve's Half-Life repository with Deathmatch Classic sources - https://github.com/ValveSoftware/halflife/tree/master/dmc
Available on ModDB - https://www.moddb.com/mods/half-life-episode-two/downloads/trinity-rendering-engine-v308f
Available on ModDB - https://www.moddb.com/mods/tyriangroundassault/downloads/tyrianga-v1-0-src
Mirrored on code.idtech.space - https://code.idtech.space/vera/halflife-wasteland-sdk
Download page on official site - http://www.thothie.com/ww/
Mirrored on github - https://github.com/a1batross/XashXT_original
Source code is a part of Spirit of Half-Life 1.0-1.2 under XENWARRIOR macro
Logic&Trick's mirror - https://files.logic-and-trick.com/#/Half-Life/Mods/Spirit%20of%20Half-Life
Available in mod archive on ModDB - https://www.moddb.com/mods/zombie-x-10-final/downloads/zombie-x-10-dle-beta6-last-version
Available on ModDB - https://www.moddb.com/mods/zxc-mod-133/downloads/zxc-mod-136-final
Mirrored on github - https://github.com/ZXCmod/ZXCmod
Branch redempt in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/redempt
OpenAG by YaLTeR - https://github.com/YaLTeR/OpenAG
malortie's recreation - https://github.com/malortie/hl-aom
Branch aom in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/aom
Reverse-engineered code: branch aomdc in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/aomdc
malortie's recreation - https://github.com/malortie/hl-asheep
Reverse-engineered code: branch asheep in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/asheep
malortie's recreation - https://github.com/malortie/hl-biglolly
Branch biglolly in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/biglolly
malortie's recreation - https://github.com/malortie/hl-blackops
Branch blackops in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/blackops
Branch caseclosed in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/caseclosed
Branch caseclosed in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/caseclosed
Branch CAd in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/CAd
Reverse-engineered code of client part by a1batross - https://github.com/FWGS/cs16-client/tree/v1.32
Reverse-engineered code of server part by nagist - https://github.com/nagist/cs16nd
Reverse-engineered code of server part by s1lentq - https://github.com/s1lentq/ReGameDLL_CS
CSO-like Xash3D-based mod, CSMoE - https://github.com/MoeMod/CSMoE
Recreation by lostgamer aka nillerusr - https://github.com/LostGamerHL/crack_life
malortie's recreation - https://github.com/malortie/hl-eftd
Reverse-engineered code: branch eftd in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/eftd
This mod uses dlls from Cleaner's Adventures
Branch CAd in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/CAd
Unkle Mike's recreation - https://hlfx.ru/forum/showthread.php?s=&threadid=5253
Reverse-engineered code: branch bshift in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/bshift
Branch induction in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/induction
Recreation by lostgamer aka nillerusr - https://github.com/LostGamerHL/hlsdk-xash3d
Reverse-engineered code: clean branch opfor in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/opfor
Spirit of Half Life: Opposing-Force Edition - https://github.com/Hammermaps-DEV/SOHL-V1.9-Opposing-Force-Edition
Reverse-engineered code: branch rebellion in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/rebellion
Branch hl_urbicide in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/hl_urbicide
malortie's recreation - https://github.com/malortie/hl-visitors
Reverse-engineered code: branch visitors in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/visitors
Branch half-secret in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/half-secret
malortie's recreation - https://github.com/malortie/hl-nato
Branch noffice in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/noffice
malortie's recreation - https://github.com/malortie/hl-poke646
Reverse-engineered code: branch poke646 in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/poke646
malortie's recreation - https://github.com/malortie/hl-poke646-vendetta
Reverse-engineered code: branch poke646_vendetta in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/poke646_vendetta
Reverse-engineered code: branch residual_point in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/residual_point
Reverse-engineered code: branch residual_point in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/residual_point
Branch sewer_beta in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/sewer_beta
Reverse-engineered code by Velaron - https://github.com/Velaron/tf15-client
malortie's recreation - https://github.com/malortie/hl-thegate
Reverse-engineered code: branch thegate in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/thegate
malortie's recreation - https://github.com/malortie/hl-theyhunger
Reverse-engineered code: branch theyhunger in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/theyhunger
They Hunger: Tactical - https://www.moddb.com/mods/they-hunger-tactical/downloads/tht-source-code-documentation
malortie's recreation - https://github.com/malortie/hl-tot
Branch tot in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/tot
Branch aghl in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/aghl
Branch bubblemod in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/bubblemod
Deathmatch Classic: Adrenaline Gamer Edition - https://github.com/martinwebrant/agmod/tree/master/src/dmc
Deathmatch Quaked - https://www.moddb.com/games/deathmatch-classic/downloads/dmq2
Branch dmc in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/dmc
Branch echoes in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/echoes
Port to HLSDK 2.4 by malortie - https://github.com/malortie/hl-invasion
Port to Linux by fmoraw - https://github.com/fmoraw/hlinvasion
Branch invasion in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/invasion
Branch hltopdown in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/hltopdown
Branch half-screwed in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/half-screwed
Port to Linux - https://github.com/fmoraw/NS
Version 1.2: branch sohl1.2 in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/sohl1.2
Just more playable version by malortie - https://github.com/malortie/hl-shall
Branch halloween in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/halloween
Version 1.5: Port to Linux - https://git.mentality.rip/a1batross/halflife-thewastes-sdk
Branch dmc in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/dmc
Branch sohl1.2 in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/sohl1.2
Branch zombie-x in hlsdk-portable - https://github.com/FWGS/hlsdk-portable/tree/zombie-x