Labor unions in the late 19th century fought for workers' rights and better conditions through key organizations like the Knights of Labor, American Federation of Labor, and American Railway Union. These groups advocated for tactics like collective bargaining, arbitration, and strikes to achieve goals such as an 8-hour workday and equal pay. However, some strikes turned violent, such as the Haymarket Square and Pullman strikes, which led to deaths and increased public distrust of unions. Unions were ultimately able to make some gains for workers through limiting work hours, regulating conditions, and preserving collective bargaining rights.