The application of hydraulic fracturing technology has long been controversial, with continuous competition between its economic benefits and environmental risks. Environmental challenges, particularly water resource depletion and pollution, remain at the core of this controversy. Achieving green, cost-effective, and sustainable management of flowback fluids have always been a critical and challenging issue in the development of unconventional oil and gas resources. A variety of coexisting resources are associated with oil and gas production, such as sandstone-type uranium deposits, geothermal resources, rock salt, potassium-rich brine, lead–zinc and precious metal ores, hydrogen sulfide, carbon dioxide, helium, mercury in natural gas, and trace elements occurring in crude oil and bitumen. For unconventional oil and gas, flowback water should not be viewed solely as a pollutant-laden industrial effluent but also as a valuable coexisting resource with distinctive utilization potential. Through scientific management and systematic resource utilization, pollution risks of flowback water can be effectively mitigated while achieving efficient resource recovery and reducing production costs. This chapter explores strategies for managing and valorizing flowback water from unconventional reservoirs, with particular emphasis on its lithium recovery potential, offering new perspectives on the green and sustainable use of co-produced resources.