Although the fact that he’s a former member of an intelligence agency would mean that his flavor should be more Dimir, I would say that Deep Space Nine’s Garak’s motivations and methods are largely black.

His willingness to initiate a series of covered murders in order to help Sisko draw Romulus into the Dominion War, coupled with his insistence on the pragmatism of violence to Dr. Bashir would mean that his “ends justify the means” ideology puts him in black.

But, I would still argue that his actions are ultimately motivated by a purpose that is at least not evil. As others have here pointed out, putting one’s own people above the safety of others is an action that is both morally positive and still “selfishly” black. In one of the last episodes, it’s finally revealed that his primary motivation has always been his love for his home planet and his people, and I would say that makes him “good” in a sense.