I started boycotting Starbucks when I learned they had partnered with Nestle for store-bought products - their Sumatra and Komodo Dragon coffees were pretty good.
I send an email every year or so to let them know, since boycotts aren’t effective if the group being boycotted doesn’t know why, with predictably apathetic responses.
Anyway, if you’re a no-Nestle person then Starbucks is on the list…