Thyme oil can be made with cooking-4, survival-4. It’s a good disinfectant, and is a decent healing salve as well, being inbetween bandages and the improvised first aid kits for healing. It takes an hour per use to make, and required not just skill, but cooking oil as well as thyme. Canola seeds can be foraged and planted or turned into cooking oil, though.
There’s also bee balm, which can make a substitute cough syrup, and mugwort, which is good for parasites.
If you’re playing a wilderness guy, I recommend foraging and planting as much thyme and bee balm as you can in spring. After you’ve got a decent supply planted you can keep any more you forage, but having a crop of that stuff is invaluable when you hit winter and can’t forage any more of it. Especially if you’ve got a cold and can’t sleep due to the coughing.