RE:IVERMECTIN As mentioned, capers are a good source of quercetin. Capers are flower buds from a Mediterranean shrub/bush and are considered the richest source of quercetin. However, they are very high in sodium, so it's not advisable to devour them in large quantities.
Here's a link that explains more about quercetin and names 100 sources from most to least:
https://www.superfoodly.com/quercetin-foods/