Even if you manage to avoid malware, the "working" part of your search is highly questionable. The "gamemodes were originally built for GMod 12 which means that many them are unlikely to work out of the box" with these repackaged versions. These cracked versions are often based on outdated builds of the game.
🔍 Garry’s Mod 11 (the 2012–2014 era) was never officially released as freeware. Any "non-Steam free" version is almost certainly a cracked, pre-SteamPipe build (often version 2013 or earlier). These copies: gmod 11 working non steam free
Modern GMod relies entirely on the Steam Workshop for single-click installation of millions of addons. Legacy, unlinked versions require manual file placement, which is prone to errors, missing texture bugs (the infamous pink-and-black grid), and frequent software crashes. Even if you manage to avoid malware, the
Free installers from unverified sources frequently bundle intrusive adware that alters your browser settings, steals cookies, and tracks your keystrokes. 🔍 Garry’s Mod 11 (the 2012–2014 era) was
Which you are trying to run this legacy software on