Fenugreek is a good one, I’ve been a fan for several years. Watch your blood sugar with it though, take it after meals. Only real downside, and it’s not major, is that there is a sort of maple syrup scent in your sweat if you take enough of it for a long enough time. Me, I like maple syrup so no problem.
Fenugreek is also phenomenal for colds.
It works much the same as Mucinex, thinning out the mucous. And it's FAR cheaper and has no side effects that I've been able to discern.