Here's a headcanon: All the HECU grunts apart from Adrian look like the original grunt model and Adrian is the only one with the high definition look. : r/HalfLife
Alien Grunt | Half-Life Resurgence - YouTube
Urby's 1999 Mercenary Grunts - Reimagined addon - Half-Life - Mod DB
Robot Grunt - Combine OverWiki, the original Half-Life wiki and Portal wiki
HL Grunts [Half-Life: Opposing Force] [Mods]
Human Grunt (old) image - In Deep mod for Half-Life - Mod DB
Half-Life - Human Grunt Speech System and Lines - YouTube
Martin Edlund - Combine Grunt (Half life Alyx Fan Art)
Half Life:Infected Grunt. by Louis-Cypher on DeviantArt