Energy harvesting (also termed energy scavenging) involves technologies and processes that capture low-grade renewable energy from ambient sources (including solar, wind, hydro, vibration, thermal, and radio waves) and convert it into usable electricity. This energy is typically employed to power small electronics, sensor networks, remote monitoring systems, and other low-power devices. Its core advantage is to provide a self-sufficient energy solution, reducing dependence on traditional power sources, enhancing system sustainability and environmental friendliness. Metamaterials have great potential in the field of energy harvesting, especially in low-frequency energy harvesting. By carefully designing metamaterial structure, the energy conversion efficiency can be significantly improved, the frequency range of energy harvesting can be expanded, and the environment energy can be captured and utilized more effectively. Research on metamaterial energy harvesters not only can promote the development of novel efficient energy harvesting technologies, but also can help develop self-powered systems, reduce dependence on traditional energy sources, and provide innovative solutions for achieving sustainable energy utilization and powering intelligent devices. This paper studies metamaterial and energy harvesting technologies, introduces harvesters that absorb energy from different energy sources (such as solar energy, sound energy, electromagnetic energy, mechanical energy).