Goldenseal is great stuff, as is elderberry (whether you use syrup or tea).  I have only ever used goldenseal in capsules because it's not available to me in any other form and I wouldn't have the first clue what to do with it anyway!

https://www.food.news/2020-09-04-natural-antibiotics-that-may-be-in-your-pantry.html

Some of these are essential oils, of course, like the myrrh, others are helpful to skin like the neem oil.  We've been using neem oil on my friend's back for some time now because she was having some sort of itching thing going on.  This seems to have helped a lot.

Many good ideas there and of course there are quite a few other natural antibiotics, as well.  Just look them up in a library book or online or whatever.  Anything listed as "natural" these days is, of course, poo-pooed by most people so be prepared for that.