Triboelectric nanogenerators (TENGs) show promise for energy harvesting and self-powered sensing in Internet-of-Things (IoT) applications; however, material wear and performance degradation under repeated operation remain key challenges. Here, we present a high-performance untethered and mechanically-durable non-contact TENG that efficiently harvests mechanical energy from object motions and natural stimuli such as wind and rain, functioning as both sustainable energy source and self-powered sensing device. The TENG is engineered from tunable multifunctional composites derived from graphite-like carbonized fallen leaves, creating a stretchable conductor and triboelectric charges reservoir integrated with charge trapping, transport, and storage capabilities. This synergistic design maximizes charge generation while enhancing retention (4,000   minutes) and output performance (95.1   V) under non-contact operation. The device maintains functionality under 100% tensile strain for over 1000 cycles and even in high humidity (~95%). It efficiently scavenges wind and rain energy and enables to power electronics at a 2   mm separation distance in non-contact mode. Furthermore, its self-powered contactless sensing enables an intelligent classification system capable of accurately identifying different egg types, highlighting its potential in smart agriculture. This eco-friendly carbonized-leaf-derived non-contact TENG promotes sustainable material recycling while advancing renewable energy harvesting and intelligent sensing for self-sufficient agricultural applications.