idtech0 (Wolfenstein 3D Engine)

idtech1 (Doom Engine)

idtech2 (Quake 1 Engine)

GoldSrc (Half-Life Engine)

idtech3 (Quake 3 Engine)

Unreal Engine

idtech4 (Doom 3 Engine)

Source (Half-Life 2 Engine)

Unreal Engine 2

IW 2.0 (Call of Duty 2 Engine)

IW 3.0 (Modern Warfare Engine)

Unreal Engine 3

Treyarch Engine

IW 4.0 (Modern Warfare 2 Engine)

idtech5 (Rage Engine)

IW 5.0 (Modern Warfare 3 Engine)

IW 6.0 (Ghosts Engine)

Sledgehammer Engine

Unreal Engine 4

Source 2 (Half-Life: Alyx Engine)

Treyarch Engine 2.0

idtech6 (Doom 2016 Engine)

IW 7.0 (Infinite Warfare Engine)

IW 8.0 (Modern Warfare 2019 Engine)

idtech7 (Doom Eternal Engine)

IW 9.0 (Modern Warfare 2 Engine)

Unreal Engine 5

idtech8 (Doom Dark Ages Engine)