Jeff Pfeffer was a very good Pitcher for Brooklyn in the 1910s, who, from 1913 to 1914, was one of the more competent players on the mound in the National League.

Pfeffer had only played seven Major League Games before the 1914 Season (two were with the St. Louis Browns in 1911), and would have likely won the 1914 Rookie of the Year, had there been one.  This began a three-year run as a top Pitcher, where he went 66-37 with a 1.99 ERA and a WHIP of 1.081.  Pfeffer helped Brooklyn win the Pennant that year, and though they lost to Boston, with Pfeffer taking a Loss, he was solid in defeat.

Pfeffer slumped in 1917 and was in the Navy in 1918, only playing one Game that year.  Upon his return to the Majors in 1919, he had two good years for Brooklyn, but a poor start in 1921 saw him traded to the Cardinals. 

With the Robins, Pfeffer had a 2.31 ERA with a record of 113 and 80.

Van Mungo was one of the most eccentric figures in Baseball, or would volatile be a better word?

Mungo did not have the luxury of playing for Brooklyn when they were a National League power, but that was no fault of Mungo, who went to four consecutive All-Star Games (1934-37).  Known for an erratic fastball, heavy drinking, and a volatile temper, Mungo was the stuff of fables, but he was also a very competent hurler.  His wildness was shown by leading the NL in Walks three times, but he also once led the league in Strikeouts and three times in SO/9.

Mungo's play fell off in the late 1930s, and was traded to a Minor League Team in 1941.  With the Dodgers, Mungo went 102-99 with a 3.41 ERA.

Jake Daubert initially thought that his first crack at the Majors would be with Cleveland, who signed him in 1908, but he never played there and was released shortly after.  A second opportunity struck a year later with Brooklyn, and this time it stuck.

Playing at First Base, Daubert had a pedestrian rookie year, batting .264 with 146 Hits, but he then went on a six-year streak where he batted over.300.  This included back-to-back Batting Titles in 1913 and 1914, with him winning the Chalmers Award, which was then the version of the MVP.  He also exhibited solid speed, swiping at least 20 Bases in six of his seasons in Brooklyn.

Daubert was traded to Cincinnati in 1919, leaving Brooklyn with 1,387 Hits and a Batting Average of .305.

After a brief run in 1924 with the Cleveland Indians, it was back to the Minors for two years before the Brooklyn Robins signed Watty Clark.  

In his second year with Brooklyn (1928), Clark proved he was there to stay, and he was a member of their starting rotation for the next four years as the top hurler on a mediocre team.  Clark led the NL in FIP in 1929 and 1932, with the latter year seeing him earn his lone 20-Win Season.  

Traded to the Giants during the 1933 Season, Clark was re-acquired by Brooklyn a summer later, but he only had one productive year in him before he rapidly declined and was out of the Majors after two Games in 1937.

For the Dodgers, Clark went 106-88 with a 3.55 ERA.