Quarry picks up the newspaper off the kitchen table and there is an article about "Sugar Bates" in the headline, written by Jonathan Tropper. Sugar Bates is Frankie Faison's character in another Cinemax series, Banshee, which Greg Yaitanes (the director/producer of Quarry) was very involved with. The article refers to a known event in the history of the character of Sugar Bates and Jonathan Tropper, the writer of the article, is the creator of Banshee.
The interesting thing is, that it suggests that Quarry and Banshee exist in the same universe.
Peter Mullan (The Broker) & Josh Randall (Detective Tommy Olsen) also worked together on Ozark (2017) as Jacob Snell & Bruce Liddell respectively.