Rube Waddell, Eddie Plank, and Rube Marquard were a step above the rest,
but there were many other lefthanded pitchers among the best of their time.
Hooks Wiltse pitched 12 years in the major leagues (1904-1915) mostly with the New York Giants. He won 139 games while losing 90, with a 2.47 Earned Run Average.
Hippo Vaughn pitched 13 years in the major leagues (1908 to 1921) mostly with the Chicago Cubs. He won 178 games while losing 137, with a 2.49 Earned Run Average.
Jesse Tannehill pitched 15 years in the major leagues (1894 to 1911) with 5 different teams. He won 197 games while losing 117, with a 2.80 Earned Run Average.
Wilbur Cooper pitched 15 years in the major leagues (1912 to 1926) mostly with the Pittsburgh Pirates. He won 216 games with 178 losses, with a 2.89 Earned Run Average.
Eppa Rixey pitched 21 years in the major leagues (from 1912 to 1933), 13 with Cincinnati and 8 with Philadelphia of the National League. He won 266 games with a 3.15 earned run average, and pitched 4494 innings (29th all time) with 290 complete games in 554 starts. He was elected to the Baseball Hall of Fame in 1946.
Babe Ruth started his career as a pitcher with the Boston Red Sox, and did not give up pitching until his trade to the New York Yankees in 1920. He had 94 wins and only 46 losses for a .671 winning percentage, with a 2.28 earned run average. He won 23 games in 1916 and 24 games in 1918. He started 3 games for Boston in their World Series appearances of 1916 and 1918, with 1 shutout, 2 complete games and a 0.87 earned run average. if he had not become such a great hitter, he might have been a Hall of Fame pitcher.
Herb Pennock pitched 22 years in the major leagues (from 1912 to 1934), 11 with the New York Yankees, 8 with the Boston Red Sox, and 4 with the Philadelphia Athletics. He won 241 games with 162 losses, and he had 249 complete games in 419 starts. He also had a 5-0 win-loss record in World Series games. He was elected to the Baseball Hall of Fame in 1948.
Starting Pitchers - (played mostly prior to 1930)
The Best Lefthanded Batters and Lefthanded Pitchers in Baseball