New nanoscale materials are being developed and adopted in various technological and agricultural sectors, indicating that the commercialization of nanomaterials and nano-assisted devices will continue to grow. Various methods are available to fabricate nanostructured samples, including conventional chemical and green synthesis. Nanopriming techniques constitute a key component of modern agricultural practice because they are adaptable and effective across a range of plant varieties and environmental factors. The present review focuses on green synthesis procedures for metal- and metal-oxide-based nanopriming agents for seed priming and includes a comparison with classical chemical methods, as well as possible applications of plant-mediated synthesised agents in sustainable agricultural technology. Green synthesis is considered the best approach for obtaining nanoscale priming materials compared to other methods because it is safe for human health and the environment and exhibits low toxicity. The challenges and limiting factors associated with the plant-based synthesis of metal and metal-oxide materials are highlighted in this review. We discussed potential applications of these synthesised products in environmental remediation and sustainable farming. We focused on removing hazardous materials (HM); promoting seed shooting and seedling improvement to enhance tolerance to salinity and drought, and to support root and plant development; and enhancing yield and antioxidant enzyme activity under stressful conditions.