One giant homage to Japanese Role Playing Games. Specifically Final Fantasy.
There are tons of homages to many places and people that Richard explains to Gumball; Chainor is a homage to China, Soppy is a homage to Sony TV, Badman is a copy of Batman, and while not a homage, Richard's doctor only has a doctorate in fine arts.
The Game Child exists in real life and was the subject of Ashens and the Quest for the Gamechild (2013)