There is Only 2 Promo Hats Or Item Still Exists And Alive These days in the Steam.

Alien Swarm & Spiral Knights

These Both Games still exist's Only 2 Free Steam Games - Promo items For Team Fortress 2

Another 3 games died and shutdown by deveoplers in 2017 Times. 4 items no longer can be get 100 % Free.

Here it's: Casperr TF2 Youtuber 1 video explained all Of 2-6 Free Steam games Promo Team Fortress 2 Items: