Many of these are digestives, which help kick the system into action before a meal -- useful in a culture that eats a lot of heavy pasta. It's like turning on the water before you turn on the garbage disposal. ;) There are other medicinal applications, such as nutrients, immunity, sleep aids, calm, resilience, etc. Most herbal goals can be pursued in this format. You just look up the herbs that do what you want, and choose the most robust ones. For liqueurs, you want tough stuff -- bark, roots, seeds, etc. -- rather than delicate things like leaves or flowers. You can include the latter too, just won't get as much good out of them.
A related category is bitters, which are famous for mixed drinks, but you can use those in other kitchen applications also. They make brilliant "secret ingredients." Generally, bitters are meant to be added in minute quantities to other things, while a liqueur or aperitif is meant to be taken alone an ounce or two at a time.
If you're shopping, check out Italian and other traditional European options. Some of the best ones have recipes hundreds or thousands of years old. They tend to work better than modern fad ones. But you can still make your own if you want to explore.
Don't use alcohol? Consider glycerin as a substitute medium, as in halal vanilla extract.