I don't see how that's applicable to green tea or fenugreek, or coffee actually.
Well I was referring to "pills and potions" which are sold as miracle diet solutions that magically make you able to stick to your 1200 calorie regime without feeling hungry.
The simple truth is that the human body is evolved to have a hunger response more frequently than it actually needs food, because we evolved to put on weight in times of plenty so that we could survive the subsequent famine. For most of us the times of plenty are every day, the times of famine are only when we choose to say no to our impulses, and there is no magic want to make those impulses go away.
I don't think the drinks you list are marketed as appetite suppressant are they? I believe they are diuretics (make you wee a lot) and so using them a lot will cause you to lose body weight in the form of water, and certainly can cause damage in the process but most users don't take enough to do themselves massive harm. Of course the lost weight goes on again as soon as you start drinking normally, except for whatever weight you lost from simply having a deficit of calories - and keeping your stomach full of liquid can help with that a little bit but it's not generally very good for you.