Russell Bufalino- Had his own, quiet family but yielded as much power as any boss in the country.

Charles "Charlie Murgie" Imburgia (LaRocca Crime Family)- I have to agree with Friend of Henry. Arguably, one of the most powerful Consigliere's in the country. He still mediated disputes and was a voice of reason between many of the Midwest crime families until the age of 92. He died in 2002, but was so low profile while owning his pizza parlor "The Sunrise Inn" that nobody advertised what he truly was...but the people who needed to know, knew.