The coronavirus disease-19 pandemic has intensified interest in the global diversity of RNA viruses and their ability to jump hosts, with a notable expansion in the number of known betacoronaviruses in wild mammalian species, particularly bats. This has enabled vaccine development research to shift its focus to include a range of severe acute respiratory syndrome coronavirus-1 and severe acute respiratory syndrome coronavirus-2 related viruses from animal species, with the intention of developing broadly protective coronavirus vaccines and therapeutics. However, there is currently a lack of synthesis of this expanding knowledge base of viruses with potential to cause another severe disease outbreak. This has led to many vaccine trials considering protection against a small subset of known betacoronaviruses that poorly approximate the true diversity of this group of viruses. This review aims to synthesize information gained from the recent surge in betacoronavirus characterization, providing a catalogue of viruses exhibiting features that pose a risk to public health, together with a framework for assessing their likelihood of emergence and subsequent transmission through human populations. This information will help inform global pandemic preparedness measures before a novel betacoronavirus outbreak occurs.