Chamberlain and Michael Shaara.
George Sears Greene is forgotten as well, with the exception of people with an interest in the battle of the Gettysburg. Culp's Hill today is the least visited section of the battlefield, despite it seeing more sustained fighting than Little Round Top and arguably being much more important strategically.
A large part of that was that Chamberlain was a very good writer, which in turn probably played a role in why Michael Shaara made him one of the characters in his novel, rather than David Ireland. Chamberlain's skill with a pen ensured he, the 20th Maine, and Little Round Top would be better remembered than Culp's Hill and it's cast of characters. Greene was an engineer that didn't have Chamberlain's skill with a pen, and Ireland didn't survive the war.