The Javier Family
This pairing of Cardinal pairings was not known to me. Julian Javier had a lengthy career in St. Louis, 12 years, and he made it to two All-Star games during his tenure. He also was a part of two World Series teams in 1964 and 1967. Julian played with a Cardinal great in Stan Musial, and the two became close friends, so much so that he named his son after The Man.
Stan Javier played for 18 years in the majors. Though none of them were with the Cardinals, he was initially signed by the Redbirds in 1981. Stan was subsequently traded to the New York Yankees the following year.
The Duncan Family
The Duncan family is chock full of professional baseball players. The dad, Dave, and his sons Chris and Shelley all played in the majors. Though Dave never played baseball with the Cardinals, he was an excellent coach. Dave Duncan was the team's pitching coach from 1996 until 2011, and he was a key cog in the team's World Series championships in 2006 and 2011.
Dave's son, Chris, did play for the Cardinals. He played outfield from 2005 until 2009, and he, too, was a part of the team's World Series efforts in 2006. Despite having a career .805 OPS, Chris Duncan retired in 2012 after a diagnosis with a brain tumor. He fought his cancer hard for 7 years, and eventually passed away on September 6th, 2019.