Based on my own experience and reading Stephen Buhner (an herbalist and author I admire) I have been obtaining some plant medicines to help me and my people through viral illness, most specifically coronaviruses.
Of course, none of us have experience treating COVID19 with herbs, cause it's new to humans. But it's in a family of viruses that we are very familiar with. Coronaviruses cause the common cold and SARS and MERS.
Elder--berries and other parts--show some effectiveness in helping people recover from coronavirus infection. So I stocked up on elderberry juice. I might harvest some stems and leaves later this spring when the plants leaf out to make into medicine.
Ginger--fresh only is recommended. I hope that includes frozen. I am adding a tablespoon or so to my morning smoothies.
Chinese Skullcap for tinctures.
I already have a great supply of Echinacea, Astragalus, and Goldenseal.
I will also be buying a big bag of onions. I have a lot of garlic remaining from the harvest last fall. And greens coming up in the garden.