Ok, usual disclaimer - I'm not making any claims for therapeutic benefits from any of these items. However in some cases I may provide links so you can read further and make up your own mind.
I became interested in many of them, through my daughter's reading on Ayurvedic medicine, and through some of the herbs & remedies used in Traditional Chinese Medicine. Finally I also really like growing things and also like a challenge. Once I found that seeds for many of these items were available via the internet, the next step was to try the ones that looked viable to the climate of the UK.
There are many sources for seeds. In addition, I've found that many companies in the US and UK will supply plants for some of these varieties. One US company I have used for seeds is: http://www.horizonherbs.com/