“Gang of Four”, the name commonly applied to the authors of the seminal book “Design Patterns”

https://en.m.wikipedia.org/wiki/Design_Patterns

Gang of Four. https://en.wikipedia.org/wiki/Design_Patterns

Not sure but I suspect it would be the "gang of four", i.e., the authors of the canonical OO design pattern book.

Gang of 4 - 4 authors from the book