Garry's Mod 1 file - Garrys Mod for Half-Life 2 - ModDB

The earliest version of Gmod, with gm_construct. You also need 7zip to open the folder.

Half-Life 2 Garry's mod

Steam Workshop::Half Life 2 Remake

Garry's Mod (2012) - The Cutting Room Floor

How To Mount Source Mods On Garry's Mod

Miscellaneous garrys mod Videos (until 2009-2010) : Free Download, Borrow, and Streaming : Internet Archive

Garry's Mod, Yogscast Wiki

Half-Life 2 Content - Gmod addon - ModDB

Half-Life 2 Campaign mod for Garry's Mod - Mod DB

Half-Life 2 Garry's mod

Garry's Mod: Half-Life 2 Beta Add-Ons! (Characters, Maps, Weapons, etc.)

Steam Workshop::Half life 2 campaign maps Full pack