"Siders" is a term that can refer to individuals who are on one side of an issue or group. Synonyms for this term include supporters, advocates, partisans, and backers. These words all refer to individuals who express a positive affiliation or support for a particular person, cause, or group. Other synonyms include allies, supporters, or champions, all of which denote individuals who work together to achieve a common goal. Additionally, you could use terms such as faction, sect, or cliques to describe groups of like-minded individuals who are united in their beliefs and opinions. Regardless of the specific term used, these synonyms all convey the idea of individuals who are committed to a particular viewpoint or cause.