Engine:Source
Source is the 3D game engine used by Valve in games such as Half-Life 2, Portal, and Counter-Strike: Source, as well as other high-profile developers and indie developers. Mods for Source Games are quite common because it is relatively "open" compared to other engines.
Games
Console Commands
Source Engine console commandsWill run on most Source games such as Portal 2, Portal, Garry's Mod, and Half-Life 2. It should also be noted that every game will have its own commands in addition to these default commands and these can also be extend at run time, such as by mods.