Nature has long been recognised as a crucial source for developing pharmaceutical agents, with many modern drug discoveries originating from naturally occurring substances. Over two-thirds of all anticancer drugs today are derived directly from unaltered natural compounds or are inspired by natural product pharmacophores. Natural products derived from plants, marine organisms, fungi, and other sources often exhibit diverse biological activities that are essential to drug discovery and development. This Reprint is a collection of articles showcasing current research and comprehensive reviews that explore natural compounds from diverse biological sources, including 1′-acetoxychavicol acetate derived from plants in the ginger family, a natural flavonoid isolated from the calyces and flowers of Roselle, a dichloromethane extract from Salvia guevarae plants of South America, and many more. Sustainability and circular use of resources are also emerging themes in natural product research, with articles in this Reprint showcasing promising pharmaceutical candidates from bio-waste. Beyond conventional plant-based sources, novel natural sources derived from bacteria and organic gemstones were also explored for their pharmaceutical activities. Collectively, these works demonstrate the growing integration of sustainability, innovation, and multidisciplinary approaches in natural product research.