Author's Notes
Goblins
The idea of the goblins mostly came from GURPS fantasy, who, as far as I know, was the first to treat them as an actual people, not just monsters.
This was mixed up with stereotypical Romani culture, which made a good fit. At this point, I want to point out that I use the stereotype, not the real culture, so don't infer anything about real Romani culture or people from it. It's good fantasy fuel, nothing more.
I also got some inspiration from the book Circus by Alistair MacLean, an agent story where a team of specialists masquerade as a circus.
What makes them good in a fantasy setting is their outsider status and their travelling culture, as well as their specific talents. It's easy to see a party of adventurers as a traveling Goblin clan.