Ensuring food for the growing population is the major challenge in the years to come. Microbial inoculants offer a long-term sustainable way to boost output without endangering the environment or public health. Abiotic and biotic stressors have become more common due to climate change, which have decreased productivity. Microbe-based biostimulants have shown to increase the productivity of soils including degraded agro-ecosystems. Rhizobacteria, soil or endophytic bacteria, endo- or ectomycorrhizal fungi, or cyanobacteria are examples of microbes that increase plant productivity in several direct and indirect ways, such as by solubilizing minerals, producing phytohormones, alleviating plant stress tolerance, and generating antipathogenic compounds. The development of bioformulations with greater shelf life, broader applicability, and ease of use has a lot of possibilities. This chapter discusses the variety of microorganisms utilized as bioinoculants and their mechanisms for increasing plant productivity. The chapter also discusses on the ability of microbes to fight various abiotic stresses and enhancement of productivity in such situations with future prospects in this field.