This presentation aims to shed light on the characteristics of Trans-Neptunian Objects (TNOs) across a broad size scale using stellar occultations, focusing on the latest outcomes from two leading observational projects: the Organized Autotelescopes for Serendipitous Event Survey (OASES) and the Trans-neptunian Atmospheres and Belts Analysis through Stellar-occultation Coordinated Observations (TABASCO). The OASES project uses multiple small (0.28 or 0.20 m aperture) telescopes, equipped with large-format CMOS cameras, to detect and study stellar occultations by unidentified kilometer-sized TNOs. Through its monitoring observations, OASES has identified a single possible occultation event by a kilometer-sized TNO, illustrating the effectiveness of serendipitous surveys in unveiling the elusive smaller members of the outer solar system objects. On the other hand, the TABASCO program employs a network of meter- to sub-meter-sized telescopes across Japan to perform multi-station observations of occultations by known TNOs of sizes around several hundred kilometers. These observations not only aim to determine the sizes and shapes of the TNOs but also to explore their atmospheres, rings, and satellites. The presentation will highlight the recent discoveries regarding the atmospheres of TNOs obtained through the TABASCO program, contributing significantly to our understanding of their physical properties. Together, these projects exemplify the power of stellar occultations in studying the outer edges of our solar system, offering new perspectives on the composition, structure, and evolution of Trans-Neptunian Objects.