Biofuels have attracted significant attention in recent years as a result of diminishing fossil fuels and increasing environmental concerns due to greenhouse gas emissions. The concept of using biofuels as energy resources is very ancient since the earlier human history. However, civilizations preferred fossil fuels over plant resources as an energy source due to their ease of availability and economic viability. Biofuels are available in solid, liquid, and gaseous states. Biodiesel, bioethanol, biomethanol, biomethane, and bio-butanol are the commonly used biofuels as a substitute of fossil fuels. Biodiesel, because of its renewable nature and environmental benefits, is a potential and more appealing fuel for diesel engines. Biodiesel accounts for the 20% production of liquid biofuels. The biodiesel feedstocks include edible oils such as sunflower, soybean, and coconut oil, as well as nonedible oils such as Jatropha, jojoba, and spent cooking oil. Acid- and base-catalyzed transesterification reactions are the widely used methods to achieve biodiesel from diverse variety of biomass. Bioethanol accounts for the 80% of worldwide production of liquid biofuels and can be an alternative solution for the current fuel issue. Significant progress in renewable biomass pretreatment, cellulase production, and co-fermentation of sugars (pentose and hexose) as well as bioethanol separation and purification has been seen in recent decades, but bioethanol is still not to the fossil fuels. The biggest challenge remains how to reduce the production cost of bioethanol. Therefore, the biorefinery concept is needed to utilize renewable feedstocks more comprehensively and to manufacture more value-added coproducts that would reduce the cost of bioethanol production. Biomethanol can be manufactured by via a variety of thermochemical processes such as pyrolysis, gasification, and liquefaction. Anaerobic digestion, alcoholic fermentation, and agrochemical methanol synthesis are the three types of metabolic pathways. Carbon dioxide, carbon monoxide, carbon, methane, and water are the most common components in the samples investigated, and they can be found in gas, liquid, or solid form. As a result, subsequent reactions of decomposing biomass material can yield methanol. Biomethane is currently the most efficient and clean-burning biofuel available. Biomethane is the most commonly used fuel in vehicles based on gaseous fuels. It may be produced from any type of biomass, even from wet biomass, which isn’t suitable for most other biofuels. Biogas is the basic ingredient of biomethane production, which can be received from a variety of sources. Biogas may be made from a considerably wider range of feedstocks than traditional liquid biofuels. The feedstock may come from a variety of sources, including livestock waste, manure, harvest surplus, and vegetable oil leftovers. Dedicated energy crops are increasingly being used as a feedstock for biogas production. Biogas collected from landfills is another source of feedstock. Bio-butanol has been renewed as a cutting-edge biofuel with exceptional qualities of application as a “drop-in” fuel. ABE fermentation technology, which was the second largest industry in the United States in the first part of the twentieth century, can be revived for bio-butanol production while also addressing environmental concerns. Many researchers have explored several aspects of this process since the 1980s, resulting in significant improvements in bio-butanol production. However, several obstacles related to the substrate, process, and strain are still existing, and research is underway to improve bio-butanol production systems.