My general guideline for flavorings is the same as it is for the foods being flavored: variety, variety, variety. I have about 15 or so flavorings lined up on a kitchen shelf, and I try to use a different one everyday (in addition to some that I use everyday). That is a way of making sure I get a wide variety of specialized substances that the flavorings contain -- if they contain any, that is. If nothing else, at least I get a variety of tastes.
Unfortunately, I usually can't eat any flavorings made from seeds (as described here http://www.aristotleadventure.com/anti-itis/
), so I try to maximize the list of flavorings I can
I would like to offer my list in hopes someone here could add to it. (I like hunting for new flavorings.) All are in dry form, and most I can buy economically in bulk in the "natural foods" section of the grocery store I go to.
I have shown below which part of the plant they come from, as far as I know. This process of accumulating flavorings has been educational for me.
(from leaves), chives
(inside of tree bark), dill
weed (leaves), garlic