Minimal replicons of circular RNA, such as viroids or deltaviruses, occupy the conceptual and evolutionary boundary between living and nonliving matter. They exemplify genomes in which RNA alone integrates heredity, self-cleaving catalysis, and parasitic adaptation to the environment, thereby providing plausible modern analogues of primordial RNA World replicators. Advances in high-throughput sequencing and planetary-scale data mining have transformed these agents from rare curiosities into a vast ecosystem of “insignificant” RNA agents such as zetaviruses, circular RNA viruses, and obelisks, associated with all major environments and host types. This expanding catalog of minimal replicators challenges traditional host-range assumptions, blurs the virus–viroid distinction, and suggests that minimal RNA-based molecular parasites have persisted and diversified throughout Earth’s history. By linking molecular fossils such as ribozymes and circular genomes to contemporary microbial ecosystems, these discoveries support the view that the RNA World is not a vanished prebiotic stage but a continuing dimension of life, and that studying minimal RNA replicons can illuminate both the origins and ongoing evolution of biological complexity.