When identifying key sources of information, one might refer to "informants," "sources," "insiders," or "confidants." These individuals are often privy to details that the general public is unaware of, and can provide valuable insights and intel. "Tipsters" may also be used, especially in the context of providing tips to law enforcement agencies or news outlets. Alternatively, "contacts" or "connections" may be used to refer to individuals who are well-connected or have significant influence within a particular field or industry. Regardless of the terminology used, having reliable in formers can be invaluable in a range of contexts, from journalism and research to politics and criminal investigations.