<p>Replacing synthetic fertilizers, growth regulators, and plant protection products with biological ones reduces environmental impacts, preserves biodiversity and soil fertility, and slows the depletion of natural resources. Plant-friendly rhizosphere microorganisms (bacteria, fungi, and algae) are of particular interest for the development of commercial bioproducts (biofertilizers, biostimulants, and biological control agents). This article presents a review of scientific publications devoted to the production and use of agricultural bioproducts (inoculants) based on plant growth–promoting bacteria (PGPR), plant growth–promoting fungi (PGPF), and eukaryotic microalgae. According to existing estimates, the biofertilizer market is expected to reach $ 2.83 billion by 2025. Large companies operating in the biofertilizer market are focusing on developing innovative products that enhance soil suppression and fertility by improving microbial diversity, increasing nutrient availability, and suppressing dangerous phytopathogens. Applying genetic engineering technologies by manufacturers is a leading trend in recent decades, allowing one to adapt inoculants to the specific needs of agricultural crops, to increase their effectiveness and resistance to adverse factors, and to ensure successful integration with native microbial communities. Key challenges in biotechnology that need to be addressed today include justifying the quality of bioproducts, extending shelf life, guaranteeing efficacy, reducing costs, and ensuring environmental and sanitary safety. It is necessary to develop technologies for the production of large quantities of pure (free from other microorganisms) inoculants with a high seeding potential to ensure the proper quality of bioproducts and the guaranteed effectiveness of their use.</p>