You can activate the command console by pressing the ~ or ¬ key on your keyboard (Whichever is next to the number 1). Please note that not every command, item or character is listed here, as the list is very long, try experimenting for yourself. :)
god - Makes you invincible and have unlimited ammo. notarget - Enemies will be unable to target you. noclip - Allows you to walk through doors, walls etc. health # - Gives you # amount of health. (Replace with a number) give all - Gives you all weapons. cg_3rd_person 1 - Switches to third person view.
Character Spawn List
Thanks to Black Ice
spawn Models/char/(name) - Replace (name) with one of the following: