jay gould(railroad Business) - Robber Baron
cornelius Vanderbilt(railroad Business - rival of Gould - anti-Robber Baron?
andrew carnegie(steel buis.) - not really a Robber Baron - Gospel of WEALTH BOOK.
john rockefeller(oil buis.) called Robber Baron by author Josephson.
Dependimg on how you view business ethics, you can call all of them robber baros or only some of them.
Appearing in literature during the late 19th century, the Robber Baron thesis was popular until the 1940s. Matthew Josephson's The Robber Barons gave the term its most enduring expression. The theme had much popularity during the Great Depression as there was widespread public scorn against big business.
But by the end of the Great Depression, other historians, notably Allan Nevins, began advocating the "Industrial Statesman" thesis. Nevins, in his John D. Rockefeller: The Heroic Age of American Enterprise (2 vols., 1940), took on Josephson directly. He argued that while Rockefeller may have engaged in unethical and illegal business practices, this should not overshadow his greater contribution of bringing order to the industrial chaos of the day. Gilded Age capitalists, according to Nevins, sought to impose their will for order and stability on the competitive business environment. Their work ultimately made the United States the foremost economy by the twentieth century.
The whole Robber-Baron-or-Industrial-Statesman debate was sidestepped by Alfred D. Chandler in The Visible Hand (1977). There Chandler contended that the business of industrializing America was a historical process and not a morality play of good versus evil. As he later expressed, "What could be less likely to produce useful generalizations than a debate over vaguely defined moral issues based on unexamined ideological assumptions and presuppositions?"[
Due to the robber barons' unethical business practices, such as the exploitation of labor, the general public typically regards these aggressive capitalists with disdain. However, some historians argue that the late-19th century entrepreneurs usually referred to as "robber barons" - including Andrew Carnegie and John D. Rockefeller - are responsible for building a large portion of the U.S.'s current economic clout, because of their large investments in burgeoning American industries. Many also went on to become high-profile philanthropists.