• The thermal drawing process enables scalable, low-cost fabrication of flexible fiber sensors with complex functionalities from nanoscale to kilometer scale.
• Thermally drawn fiber sensors cover a wide range of stimuli including temperature, acoustic, mechanical, chemical, biological, optoelectronic, and multifunctional sensing.
• The review highlights material selection criteria and structural design principles for optimizing sensor performance.
• Future developments focus on improving material stability, multifunctional integration, and practical applications in smart textiles and wearable devices.