I describe my GURPS Everything campaign from the 1990s. By "everything", I mean I allowed the players to use any skill or ability from any GURPS sourcebook. Fun times ensued.
Videos I reference:
How Fallout was made SPECIAL: https://www.youtube.com/watch?v=kgPwfHXiBjw
An "Off The Rails" TTRPG Campaign: https://www.youtube.com/watch?v=tv74Z8rByAY