Ivermectin is one, the importance of which to humanity resulted in the discoverer/developer receiving the Nobel Prize, for ending the suffering of hundreds of millions of people around the world.
Saving the lives and preventing the suffering of at least tens of millions of people from COVID-19, overtly starting in April of 2020, but that doesn't count Africa being prophylaxed for COVID-19 with IVM (though HCQ may have been more significant)
decades before the SARS-CoV-2 virus was even invented and patented.
With so many more anti-viral applications recognized!
https://www.nature.com/articles/s41429-020-0336-z
"Several studies reported antiviral effects of ivermectin on RNA viruses such as Zika, dengue, yellow fever, West Nile, Hendra, Newcastle, Venezuelan equine encephalitis, chikungunya, Semliki Forest, Sindbis, Avian influenza A, Porcine Reproductive and Respiratory Syndrome, Human immunodeficiency virus type 1, and severe acute respiratory syndrome coronavirus 2. Furthermore, there are some studies showing antiviral effects of ivermectin against DNA viruses such as Equine herpes type 1, BK polyomavirus, pseudorabies, porcine circovirus 2, and bovine herpesvirus 1."
Even "
Ivermectin, a potential anticancer drug derived from an antiparasitic drug"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7505114/