Supplementary Materials The following are available online at https://www.mdpi.com/1999-4915/12/10/1092/s1, Figure S1: The chemical structure of tenofovir disoproxil and schematic representation of its metabolic bioactivation, Figure S2: The chemical structure of tenofovir alafenamide and schematic representation of its metabolic bioactivation, Figure S3: The chemical structure of AT-527 and schematic representation of its metabolic bioactivation, Figure S4: The chemical structure of danoprevir and maraviroc, Figure S5: The chemical structures of three natural products that are currently being tested against COVID-19, Figure S6: The chemical structures of various agents with potential antiviral activity attributed to various mechanisms. Click here for additional data file. Author Contributions Conceptualization, R.A.A.-H.; writing—original draft preparation, R.A.A.-H. and S.K.; writing—review and editing, R.A.A.-H. and S.K.; visualization, R.A.A.-H.; supervision, R.A.A.-H.; project administration, R.A.A.-H.; funding acquisition, R.A.A.-H. All authors have read and agreed to the published version of the manuscript. Funding R.A.A.-H. is supported by grants from National Institute of General Medical Sciences under the award numbers SC3GM131986 and P20GM103424. The content is solely the responsibility of the authors and does not necessarily represent the official views of NIH. Conflicts of Interest The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. Abbreviations 3CLpro 3-Chymotrypsin-like protease ACE2 Angiotensin converting enzyme 2 ADALP1 Adenosine deaminase like protein 1 CES1 Carboxylesterase 1 COVID-19 Coronavirus infectious disease of 2019 CRM1 Chromosome region maintenance 1 ERGIC Endoplasmic reticulum–Golgi intermediate compartment GTP Guanosine triphosphate GUK1 Guanylate kinase 1 HINT1 Histidine triad nucleotide-binding protein 1 HBV Hepatitis B virus HCV Hepatitis C virus HIV Human immunodeficiency virus INF Interferon IL Interleukin MERS-CoV Middle East respiratory syndrome coronavirus Mpro Main protease NDPK Nucleoside diphosphate kinase NSAIDs Nonsteroidal anti-inflammatory drugs NSP Nonstructural protein NF-AT Nuclear factor of activated T-cells mTOR Mammalian target of rapamycin PLpro Papain-like protease RdRp RNA-dependent RNA polymerase SARS-CoV Severe acute respiratory syndrome coronavirus SARS-CoV-2 Severe acute respiratory syndrome coronavirus-2 TRMPSS2 Transmembrane protease serine 2